A liquid-deficiency alarm of an infusion apparatus is characterized by comprising an infusion apparatus observing
pipe 1, a floating ball 2, magnets 3, a reed
pipe 4, a battery 5, a
signal processor 6, a
loudspeaker 7 and an indicator light 8, wherein the magnets 3 are mounted in the floating ball 2 and put in the infusion apparatus observing
pipe 1, the reed pipe 4 is mounted at the outer lower part of the infusion apparatus observing pipe 1, two
external connection wires of the reed pipe 4 are connected in series with the battery 5 and the
signal processor 6, and an output end of the
signal processor 6 is connected with the
loudspeaker 7 and the indicator light 8. In the infusion process, a liquid is arranged in the infusion apparatus observing pipe, the floating ball is always located at the upper part of the infusion apparatus observing pipe under the
buoyancy of the liquid, when the reed pipe of the alarm of the infusion apparatus doesn't detect a
magnetic field emitted by the magnets, the reed pipe is in a normally open state, and the alarm doesn't work; when an infusion
bottle contains no liquid, the floating ball moves downwards with reduction of the liquid in the observing pipe; when the floating ball moves to the bottom of the observing pipe, the reed pipe is in a
closed state under the action of the
magnetic field, at the moment, a circuit is formed in the alarm, the alarm gives an alarm, and the indicator light gives out light to remind a nurse or an accompanying person of replacing the infusion
bottle for a patient.