It is possible to reduce power consumption of a pulsimeter. A pulsimeter 2 includes a light emitter 10, a photodetector 12, a sample and hold circuit 20, an AD converter 14, and a time measurement unit 22. The light emitter 10 periodically repeats a light emission for a predetermined period of time to a blood vessel of a measurement target. The photodetector 12 detects light emitted by the light emitter 10 via the blood vessel. The sample and hold circuit 20 takes and holds an output voltage of the photodetector 12. The AD converter 14 analog/digital converts an output voltage of the sample and hold circuit 20. The time measurement unit 22 measures a time for an output of the sample and hold circuit to be constant. A light emitting time of the light emitter is set by the time measured by the time measurement unit 22.
