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