The electronic sphygmomanometer

A power supply unit of an electronic sphygmomanometer includes: a dry cell (52) as a primary battery, a rechargeable battery (51) as a secondary battery and a power control circuit (53). A voltage detector (56) detects a voltage (a characteristic value) of the rechargeable battery (51) and a voltage detector (57) detects the voltage of the dry cell (52). A switching control unit (102) performs a shift control of the dry cell (52) and the rechargeable battery (51) by, based on a detection result by the voltage detectors (56, 57).