Muscle water content measuring device

Abstract

To suppress the effects of noise and improve measurement accuracy. [Solution] The skin moisture content measuring device of the present disclosure is a skin moisture content measuring device that measures the moisture content in the skin of a living body, and includes a signal output unit that outputs an AC signal, a first impedance element, a first electrode to which the AC signal is applied via the first impedance element, a second electrode to which a ground voltage is applied, and an arithmetic processing unit that calculates the moisture content based on the voltage of the first electrode when the first electrode and the second electrode are brought into contact with the skin.

Description

[Technical Field]

[0001] The present invention relates to a skin moisture content measuring device. [Background technology]

[0002] A technique for measuring moisture content is known (see, for example, Patent Document 1) in which two electrodes are placed in contact with the skin of a living body (e.g., a human body), an AC signal (rectangular wave signal) is applied between the electrodes, and the impedance of the skin surface is measured. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-176120 Summary of the Invention [Problem to be solved by the invention]

[0004] The device disclosed in Patent Document 1 reads the current passed through the living body, and is therefore susceptible to noise during measurement, which can lead to a decrease in measurement accuracy.

[0005] The present invention has been made in consideration of the above-mentioned conventional problems, and aims to provide a skin moisture content measuring device that can suppress the effects of noise and improve measurement accuracy. [Means for solving the problem]

[0006] The main invention that solves the above-mentioned problems is a skin moisture content measuring device that measures the moisture content in the skin of a living body, and is equipped with a signal output unit that generates and outputs an AC signal, a first impedance element, a first electrode to which the AC signal is applied via the first impedance element, a second electrode to which a ground voltage is applied, and an arithmetic processing unit that calculates the moisture content based on the voltage of the first electrode when the first electrode and the second electrode are brought into contact with the skin.

[0007] Other features of the present invention will become apparent from the following description and drawings. [Effects of the Invention]

[0008] According to the present invention, it is possible to suppress the influence of noise and improve measurement accuracy. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing the configuration of a general skin moisture content measuring device 100. [Figure 2] 1 is a diagram showing the configuration of a skin moisture content measuring device 10 according to a first embodiment. [Figure 3] FIG. 10 is a diagram showing the results of a simulation of changes in detection voltage due to the impedance of a living body. [Figure 4A] 3A and 3B are diagrams showing examples of the shapes of a first electrode 12 and a second electrode 13. FIG. [Figure 4B] 10 is a diagram showing a first modified example of the shapes of the first electrode 12 and the second electrode 13. FIG. [Figure 4C] 10 is a diagram showing a second modified example of the shapes of the first electrode 12 and the second electrode 13. FIG. [Figure 5] FIG. 10 is a flowchart showing an example of a startup operation. [Figure 6] FIG. 10 is a diagram showing the configuration of a skin moisture content measuring device 10A according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] At least the following matters will become clear from the description of this specification and the accompanying drawings. In addition, the same or equivalent components, members, etc. shown in each drawing will be denoted by the same reference numerals, and redundant explanations may be omitted as appropriate.

[0011] In this embodiment, "connection" refers to an electrically connected state unless otherwise specified. Therefore, "connection" includes not only cases where two components are connected by wiring, but also cases where two components are connected via, for example, a resistor.

[0012] =====First Embodiment====== <<General skin moisture measurement device>> Before describing the skin moisture content measuring device of this embodiment, a general skin moisture content measuring device will be described.

[0013] FIG. 1 is an explanatory diagram of the configuration of a typical skin moisture content measuring device 100. The diagram also shows an equivalent circuit of a living organism (e.g., a human body). Specifically, the equivalent circuit for high-frequency current in the skin of a living organism can be thought of as a parallel circuit of a resistance component R and a capacitance component C, as shown in FIG. 1. It is also known that when the moisture content of the skin (hereinafter referred to as skin moisture content) changes, both the resistance component R and the capacitance component C change.

[0014] When a weak high-frequency current (AC signal) is passed through the skin of a living body, the electricity flows along the moisture, which has good conductivity. By measuring the impedance at this time, the moisture content of the skin can be measured. In this embodiment, the "AC signal" refers to a signal whose magnitude changes periodically over time, specifically a square-wave signal (pulse signal). However, a sine wave or the like may also be used.

[0015] The skin moisture content measuring device 100 shown in FIG. 1 includes a device main body 110, an output electrode 120, and an input electrode .

[0016] The output electrode 120 and the input electrode 130 are parts that come into contact with the skin of a living organism (e.g., a human body), and are each connected to the device main body 110 via wiring or the like. The output electrode 120 is an electrode for applying an output signal (AC signal) from the device main body 110 to the skin of the living organism. The input electrode 130 is an electrode for inputting a signal that has passed through the living organism to the device main body 110. With the output electrode 120 and the input electrode 130 in contact with the skin surface of the living organism, the skin moisture content can be determined based on the flow of a current between the electrodes.

[0017] The device main body 110 constitutes the main body of the skin moisture content measuring device 100. The device main body 110 includes an AC signal output section 111, an input signal processing section 112, a power supply 114, and a resistor R0.

[0018] The AC signal output unit 111 outputs a rectangular wave AC signal (pulse signal Vp) with an amplitude of several volts (e.g., 3 V), a predetermined frequency, and a predetermined pulse width. The pulse signal Vp output from the AC signal output unit 111 is applied to the output electrode 120.

[0019] The resistor R0 is provided between the input electrode 130 and the ground. The resistor R0 is a resistor for converting the current flowing through the input electrode 130 into a voltage.

[0020] The input signal processing unit 112 is connected to the connection point between the input electrode 130 and the resistor R0. A voltage V0 generated across the resistor R0 is input to the input signal processing unit 112. Based on this voltage V0, the input signal processing unit 112 determines (measures) the moisture content of the skin of the living body.

[0021] The power supply 114 supplies a power supply voltage for operating each circuit of the skin moisture content measuring device 100 .

[0022] The pulse signal Vp output from the AC signal output unit 111 is applied to the skin of the living body via the output electrode 120. Then, a current flows through the impedance of the living body (capacitance component C and resistance component R) along a path from the input electrode 130 to resistor R0 to ground. At this time, the input signal processing unit 112 measures the voltage V0 generated across resistor R0, and can thereby determine the moisture content of the living body's skin.

[0023] However, in this type of skin moisture content measuring device 100, both the output electrode 120 and the input electrode 130 are floating from the reference potential (here, the ground potential) of the circuit, making them susceptible to the influence of external noise during measurement, which may result in a deterioration in measurement accuracy due to the influence of noise.

[0024] Therefore, in this embodiment, the influence of noise is suppressed to improve measurement accuracy.

[0025] <<Skin moisture content measuring device of this embodiment>> FIG. 2 is a diagram showing the configuration of the skin moisture content measuring device 10 of the first embodiment.

[0026] The skin moisture content measuring device 10 of this embodiment includes a device main body 11 and two electrodes (a first electrode 12 and a second electrode 13).

[0027] The first electrode 12 and the second electrode 13 are parts that come into contact with the skin of a living body, similar to the two electrodes (output electrode 120 and input electrode 130) of the skin moisture content measuring device 100 (FIG. 1). However, in this embodiment, one of the two electrodes (specifically, the first electrode 12) serves as both an output and an input, and the other (the second electrode 13) is grounded (i.e., a ground voltage is applied).

[0028] The device main body 11 includes a CPU 20, a resistor R1, a low-pass filter 30, a power supply 40, a display unit 60, and a speaker .

[0029] The CPU 20 is a circuit that controls the operation of each part of the skin moisture content measuring device 10. When the CPU 20 executes a program (skin moisture content measurement program) stored in a storage unit (not shown), functional blocks (AC signal output unit 21, input signal receiving unit 22, and calculation processing unit 23) as shown in Fig. 2 are realized within the CPU 20.

[0030] 1, AC signal output unit 21 outputs a square-wave pulse signal Vp with an amplitude of several volts. Note that AC signal output unit 21 corresponds to the "signal output unit," and pulse signal Vp corresponds to the "AC signal."

[0031] Furthermore, although the AC signal output unit 21 is configured using functional blocks of the CPU 20, it is not limited to this. Specifically, it may be a hardware circuit that outputs a rectangular wave pulse signal with an amplitude of several volts.

[0032] The AC signal output unit 21 of this embodiment can change the frequency of the output pulse signal Vp, for example, within a range of 5 Hz to 100 kHz, in response to a predetermined instruction (for example, an instruction by a user operation). The pulse width of the pulse signal Vp can also be changed, for example, within a range of 5 μS to 100 mS. In this embodiment, the maximum amplitude (voltage amplitude) of the pulse signal Vp depends on the power supply voltage (battery voltage) of the power supply 40.

[0033] The input signal receiving unit 22 is connected to the output of a low-pass filter 30, which will be described later, and serves as an interface circuit that receives the output of the low-pass filter 30. Here, the voltage of the first electrode 12 (voltage V1 of a node N1, which will be described later) is input to the input signal receiving unit 22 via the low-pass filter 30.

[0034] Although the input signal receiving unit 22 is configured by the functional blocks of the CPU 20, it is not limited to this and may be realized by a hardware circuit.

[0035] The arithmetic processing unit 23 causes the AC signal output unit 21 to output the pulse signal Vp, and performs arithmetic processing to calculate the skin moisture content based on the input result (detection result) from the input signal receiving unit 22. Then, the arithmetic processing unit 23 causes the display unit 60 to display the calculated skin moisture content.

[0036] Although the arithmetic processing unit 23 is configured by the functional blocks of the CPU 20, it is not limited to this and may be realized by a hardware circuit.

[0037] Resistor R1 is connected between AC signal output unit 21 and first electrode 12. When first electrode 12 and second electrode 13 are brought into contact with a living body, resistor R1 is connected in series to the impedance of the living body (resistance component R and capacitance component C connected in parallel) via first electrode 12. As a result, a voltage V1 (divided voltage) is generated at the connection point (hereinafter also referred to as node N1) between resistor R1 and first electrode 12, where the voltage of the AC signal is divided by the impedance of the living body and resistor R1. Resistor R1 also serves as a resistor for limiting the output current and has the effect of protecting the living body from overcurrent. Resistor R1 corresponds to a "first impedance element." Although resistor R1 is used as the impedance element here, other impedance elements (such as a capacitor or a coil) may also be used.

[0038] The low-pass filter 30 is a circuit for removing high-frequency components (noise) from a signal. The low-pass filter 30 includes a resistor R2 and a capacitor C2. The resistor R2 and the capacitor C2 are connected in series between a node N1 and the ground. The voltage at the connection point between the resistor R2 and the capacitor C2 is the output of the low-pass filter 30 and is input to the input signal receiving unit 22.

[0039] The power supply 40 supplies a power supply voltage for operating each circuit of the skin moisture content measuring device 10. The power supply 40 in this embodiment is, for example, a battery such as a dry cell, a lithium battery, or a button battery.

[0040] The display unit 60 is, for example, a display, and as described above, displays the skin moisture content calculated by the calculation processing unit 23. If an abnormality is determined in the no-load calibration (described later), the display unit 60 displays an indication that an abnormality has occurred. The speaker 70 generates a sound to indicate the abnormality.

[0041] <<Operation of Skin Moisture Amount Measuring Device 10>> When the user turns on the power switch (not shown) of the skin moisture content measuring device 10, the power supply voltage of the power supply 40 is supplied to each part of the device main body 11. This puts the skin moisture content measuring device 10 into an operable state.

[0042] Next, the user brings the first electrode 12 and the second electrode 13 into contact with the surface of the skin of the living body and presses, for example, a measurement button (not shown), which starts measurement of the skin moisture content.

[0043] The calculation processing unit 23 of the CPU 20 causes the AC signal output unit 21 to output a predetermined pulse signal Vp. A current due to the pulse signal Vp flows through the resistor R1, node N1, first electrode 12, (living body), second electrode 13, and ground. The voltage V1 (divided voltage) at the node N1 at this time is input to the input signal receiving unit 22 via the low-pass filter 30.

[0044] The calculation processing unit 23 calculates the skin moisture content based on the input voltage (hereinafter also referred to as the detected voltage) of the input signal receiving unit 22, and causes the display unit 60 to display the calculated value.

[0045] Furthermore, the impedance of the body varies greatly depending on the condition of the skin and individual differences.

[0046] 3 is a diagram showing the results of a simulation of changes in detection voltage due to the impedance of a living body. As mentioned above, the detection voltage is the input voltage to the input signal receiving unit 22 (the output voltage of the low-pass filter 30). Here, the waveform is shown when the capacitance component C of the living body is 1000 pF (constant) and the resistance component R is in the range of 3 kΩ to 1 MΩ.

[0047] The pulse signal output from the AC signal output unit 21 has a rectangular shape. In contrast, the detection voltage has a waveform that changes gradually as shown in FIG. 3, due to passing through the low-pass filter 30. For example, when the voltage reaches a high level, the voltage rises according to the time constant of the resistor R2 and the capacitor C2, resulting in a gentle slope. This makes it possible to remove high-frequency noise.

[0048] 3, the resistance component R varies from 3 kΩ to 1 MΩ, and in this embodiment, it can be seen that when the impedance of the living body (here, the resistance component R) is low, the detection level also becomes small. From this relationship, the impedance of the living body (in other words, the skin moisture content) can be obtained from the detected voltage.

[0049] As mentioned above, the AC signal output unit 21 can change the frequency of the pulse signal, for example, within a range of 5 Hz to 100 kHz, and the pulse width, for example, within a range of 5 μS to 100 mS, in response to a predetermined instruction. Changing the frequency or pulse width in this way changes the detected voltage and waveform, so that by combining these, it is possible to improve measurement accuracy and expand the measurement range. Furthermore, by switching between multiple frequencies and pulse widths during measurement, it is possible to determine each component of the biological impedance (capacitance component C, resistance component R) from the measurement results.

[0050] As explained above, in the skin moisture content measuring device 10 of this embodiment, the first electrode 12 serves as both an output and an input (the resistance between the output and input is zero), and the second electrode 13 is grounded. This makes the potential more stable and less susceptible to noise compared to the skin moisture content measuring device 100 of Fig. 1. This improves the accuracy of the measurement.

[0051] <About the shape of the electrode> FIG. 4A is a diagram showing an example of the shape of the first electrode 12 and the second electrode 13. The first electrode 12 and the second electrode 13 in FIG. 4A have the same shape (circular cross section). An insulator 50 is provided around the first electrode 12 and the second electrode. However, this is not limiting, and for example, the first electrode 12 and the second electrode 13 may each be a cable covered with an insulator on the outside. By grounding the second electrode 13, the living body is maintained at ground potential (GND) as seen from the device (device main body 11A), so the potential of the first electrode 12 is stable and less susceptible to noise.

[0052] FIG. 4B is a diagram showing a first modified example of the shapes of the first electrode 12 and the second electrode 13. In FIG. 4B, a plurality of second electrodes 13 (three in this example) are provided around the first electrode 12. Alternatively, the area of ​​the second electrode 13 may be larger than the area of ​​the first electrode 12. Furthermore, an insulator 50 is provided between the first electrode 12 and the second electrode 13. In this case, the first electrode 12 and the second electrode 13 may each be a cable whose outside is covered with an insulator. In the case of this first modified example, the increased area of ​​the grounding portion makes operation more stable and less susceptible to noise.

[0053] 4C is a diagram showing a second modified example of the shapes of the first electrode 12 and the second electrode 13. In FIG. 4C, the first electrode 12 and the second electrode 13 are configured as a cable K in which the first electrode 12 is the inner conductor and the second electrode 13 is the outer conductor. This is the same configuration as a so-called coaxial cable. In this case, the second electrode 13 is disposed around (surrounding) the first electrode 12, so that the first electrode 12 is shielded by the second electrode 13. This makes it even less susceptible to the effects of noise.

[0054] <About calibration> In the skin moisture content measuring device 100 of FIG. 1, when the output electrode 120 and the input electrode 130 are not in contact with the living body (no load state), no current path is created and therefore no current flows.

[0055] In contrast, in the skin moisture content measuring device 10 of this embodiment, even when the first electrode 12 and the second electrode 13 are not in contact with the living body (even in a no-load state), current can flow through the path of the AC signal output unit 21 → resistor R1 → node N1 → low-pass filter 30 → input signal receiving unit 22. Therefore, for example, when the device is started up, calibration can be performed to determine whether or not there is an abnormality. Note that an abnormality may occur, for example, when a foreign object is attached between the first electrode 12 and the second electrode 13. In addition, there may be cases where the internal circuitry (resistors, etc.) of the device has deteriorated, or the voltage of the power supply 40 has changed due to temperature, etc.

[0056] FIG. 5 is a flow diagram showing an example of the operation at the time of startup. When the user turns on the power switch (not shown) of the skin moisture content measuring device 10, the skin moisture content measuring device 10 starts up (S01).

[0057] The arithmetic processing unit 23 causes the AC signal output unit 21 to output a pulse signal within a predetermined period of time from startup, and acquires the voltage V1 at the node N1 via the low-pass filter 30 and the input signal receiving unit 22 (S02). Then, the arithmetic processing unit 23 determines whether the acquired voltage V1 is within a predetermined range (S03). Here, the predetermined period is, for example, a period shorter than the period until the first electrode 12 and the second electrode 13 are brought into contact with the living body, and is, for example, 10 ms.

[0058] If the voltage V1 is within the predetermined range (S03; YES), the user presses a measurement button (not shown), and the calculation processing unit 23 starts measurement (S04).

[0059] On the other hand, if voltage V1 is not within the predetermined range (S03: NO), calculation processing unit 23 outputs an alarm or the like indicating an abnormality (S05). For example, it may cause display unit 60 to display an error or emit light, or it may generate a sound indicating an abnormality from speaker 70. This allows the user to be notified that an abnormality has occurred even when first electrode 12 and second electrode 13 are not in contact with the living body.

[0060] The predetermined range is, for example, the range of voltage V1 that can be taken when the first electrode 12 and the second electrode 13 are in an open state, and is determined taking into account manufacturing variations and temperature changes in the resistance values ​​of resistors R1 and R2.

[0061] Here, the presence or absence of an abnormality is determined, but the measured value of skin moisture content may be corrected (for example, by adjusting the gain of the input signal receiving unit 22) according to the magnitude of the voltage V1 acquired in a no-load state (within a predetermined time after startup). This can improve the accuracy of skin moisture content measurement.

[0062] ===== Second Embodiment ===== 6 is a diagram showing the configuration of a skin moisture content measuring device 10A according to the second embodiment. The device main body 11A of the skin moisture content measuring device 10A according to the second embodiment includes a CPU 20A, resistors R1 and R1A, a low-pass filter 30, a power supply 40, and a switch SW. Note that the display unit 60 and speaker 70 are not shown here.

[0063] The resistor R1A has a resistance value different from that of the resistor R1. One end of each of the resistors R1 and R1A is connected to the first electrode 12 via the node N1.

[0064] The switch SW is provided between the other ends of the resistors R1 and R1A and the AC signal output unit 21 of the CPU 20A. Therefore, the resistors R1 and R1A are provided between the AC signal output unit 21 and the first electrode 12. As described above, the resistor R1 corresponds to the "first impedance element," and the resistor R1A corresponds to the "second impedance element."

[0065] The switch SW outputs the output (pulse signal) of the AC signal output unit 21A to either the resistor R1 or the resistor R1A (that is, switches the current path).

[0066] The calculation processing unit 23A switches the switch SW so that the detected voltage during measurement is, for example, 5 / 100 to 95 / 100 times that during no load. Note that the measurement accuracy is best when the impedance of the living body (skin impedance) and the impedance in the device main body 11A (here, resistor R1 or resistor R1A) are the same.

[0067] In this embodiment, the arithmetic processing unit 23A of the CPU 20A switches the switch SW. This makes it possible to automatically select an impedance suitable for measurement. However, this is not limited to this, and for example, the user may manually switch the switch SW. Also, in this embodiment, two resistors (resistors R1 and R1A) with different resistance values ​​are provided in parallel, but the number is not limited to two and may be three or more. The resistors (current paths) may be switched by the switch SW. Also, other impedance elements (such as a capacitor or a coil) may be provided instead of resistors.

[0068] ===Summary=== The skin moisture content measuring device 10 of this embodiment has been described above. The skin moisture content measuring device 10 comprises an AC signal output unit 21, a resistor R1, a first electrode 12, a second electrode 13, and an arithmetic processing unit 23. The AC signal output unit 21 outputs a predetermined pulse signal (AC signal). The pulse signal is applied to the first electrode 12 via the resistor R1. A ground voltage is applied to the second electrode 13. The arithmetic processing unit 23 calculates the skin moisture content based on the voltage of the first electrode 12 when the first electrode 12 and the second electrode 13 are brought into contact with the skin of a living body. As a result, the second electrode 13 is grounded, making it less susceptible to noise. This reduces the effects of noise and improves measurement accuracy.

[0069] The skin moisture content measuring device 10 also includes a low-pass filter 30 connected to the first electrode 12, and the calculation processing unit 23 calculates the skin moisture content based on the output of the low-pass filter 30. This allows the low-pass filter 30 to remove high-frequency noise, thereby suppressing the effects of noise.

[0070] 4C, the first electrode 12 and the second electrode 13 are configured as a cable K in which the first electrode 12 is an inner conductor and the second electrode 13 is an outer conductor. This allows the first electrode 12 to be shielded by the second electrode 13, making it even less susceptible to the effects of noise.

[0071] The skin moisture content measuring device 10A of the second embodiment also includes a resistor R1A and a switch SW that outputs an AC signal to either the resistor R1 or the resistor R1A, and the resistors R1 and R1A are provided between the AC signal output unit 21 and the first electrode 12. This makes it possible to select either the resistor R1 or the resistor R1A that is more suitable for measurement.

[0072] Furthermore, the arithmetic processing unit 23A of the second embodiment switches the switch SW so that the voltage of the first electrode 12 falls within a predetermined range (specifically, a range from 5 / 100 to 95 / 100 times that when there is no load), thereby making it possible to automatically select a resistance suitable for measurement.

[0073] Furthermore, the AC signal output unit 21 changes at least one of the frequency and pulse width of the pulse signal based on a predetermined instruction, thereby improving measurement accuracy and expanding the measurement range.

[0074] Furthermore, the calculation processing unit 23 acquires the voltage V1 of the first electrode 12 within a predetermined period after the skin moisture content measuring device 10 is started, and if the acquired voltage V1 is not within a predetermined range, it outputs an abnormality. This makes it possible to notify the user that an abnormality has occurred even when the first electrode 12 and the second electrode 13 are not in contact with the living body.

[0075] ===Other=== The above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention may be modified or improved without departing from the spirit thereof, and it goes without saying that the present invention includes equivalents thereof.

[0076] In the above embodiment, a battery is used as the power supply 40, but it is not limited to a battery. For example, a commercial power supply may be used. [Explanation of symbols]

[0077] 10,10A skin moisture measuring device, 11,11A device body, 12 first electrode, 13 second electrode, 20,20A CPU, 21 AC signal output section, 22 input signal receiving unit, 23 arithmetic processing unit, 30 low-pass filter, 40 power supply, 50 insulators, 60 display, 70 speaker, 100 Skin moisture measuring device, 110 Device itself, 111 AC signal output unit, 112 input signal processing unit, 114 Power supply, 120 output electrode, 130 input electrode, R resistance component, C capacitance component, R0, R1, R1A, R2 resistors, C2 capacitor

Claims

1. A skin moisture content measuring device for measuring the moisture content of the skin of a living body, comprising: a signal output unit that outputs an AC signal; a first impedance element; a first electrode to which the AC signal is applied via the first impedance element; a second electrode to which a ground voltage is applied; a processing unit that calculates the moisture amount based on a voltage of the first electrode when the first electrode and the second electrode are brought into contact with the skin; A skin moisture content measuring device comprising:

2. The skin moisture content measuring device according to claim 1, a low-pass filter connected to the first electrode; The calculation processing unit calculates the moisture content based on the output of the low-pass filter. Skin moisture measuring device.

3. The skin moisture content measuring device according to claim 1, a cable having the first electrode as an inner conductor and the second electrode as an outer conductor; Skin moisture measuring device.

4. The skin moisture content measuring device according to claim 1, a second impedance element; a switch that outputs the AC signal to either the first or second impedance element; Furthermore, the first and second impedance elements are provided between the signal output unit and the first electrode; Skin moisture measuring device.

5. The skin moisture content measuring device according to claim 4, the arithmetic processing unit switches the switch so that the voltage of the first electrode falls within a predetermined range. Skin moisture measuring device.

6. The skin moisture content measuring device according to claim 1, the signal output unit changes at least one of the frequency and the pulse width of the AC signal based on a predetermined instruction. Skin moisture measuring device.

7. The skin moisture content measuring device according to any one of claims 1 to 6, The calculation processing unit acquires the voltage of the first electrode within a predetermined period after the skin moisture content measuring device is started, and outputs an abnormality if the acquired voltage of the first electrode is not within a predetermined range. Skin moisture measuring device.

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