Immediately after a main switch is turned ON, a battery check is performed based on a first inhibit voltage lower than a second reference voltage which is an inhibit voltage level a predetermined time period after the main switch is turned ON, and therefore, even when the voltage is in a low state immediately after the main switch is turned ON, it is possible to activate a camera without an erroneous detection. Further, when the elapsed time from a time when the main switch is turned OFF to a time when tuned ON next time is relatively long, a solid high polymer film inside the fuel cell is assumed to be further dried, then the first inhibit voltage is changed, and therefore, even when the voltage fluctuates depending on the humidifying state immediately after the main switch is turned ON, an appropriate battery check can be performed.