To solve the problem in which: in acquiring a white reference value, when a support plate is in a state of opening a measurement window, an appropriate white reference value cannot be acquired, and when the support plate is in a state of closing the measurement window, the color of an object to be measured cannot be appropriately measured.SOLUTION: A color measuring device comprises: an opening that is formed in an opening forming member arranged on a bottom face of the device for taking light arriving from an object to be measured into the device; an incident light
processing unit that processes the light incident through the opening; a
shutter unit that is displaceable between a closing position for covering the opening and an opening position for opening the opening, the
shutter unit having a reflection
reference surface to be a reference of a reflectance at a position facing the opening; and detection means that changes a detection
signal to be output according to the displacement of the
shutter unit.SELECTED DRAWING: Figure 44