A medical image diagnostic apparatus which processes a medical image of a subject is shown. The apparatus includes the following. A power supply supplies power to each unit of the medical image diagnostic apparatus. A power supply button receives operation to end or start the medical image diagnostic apparatus. A power supply controller stands by to receive input of the power supply button and supplies power to the power supply and controls the power supply. A battery is mounted in the medical image diagnostic apparatus and supplies power to the power supply controller. A switch receives operation to switch between on and off, and electrically connects or cuts a path between the battery and the power supply controller in response to the operation.
