To provide an electronic apparatus device that can increase a lifetime of a battery used as a driving source for an electronic apparatus device body and highly accurately estimate a lifetime of the battery with a low-cost and simple method.

An electronic apparatus device includes: a capacitor storing driving energy for an electronic apparatus device body and supplying power to the electronic apparatus device body; a battery connected to the capacitor via a normally-opened (normally-OFF) type switch, for charging the capacitor when the switch is closed (ON); a power supply control unit controlling charging of the capacitor so that a terminal voltage of the capacitor is detected, and when the terminal voltage is reduced to a preset discharge management voltage, the switch is closed, and when a preset charging time has passed, the switch is opened; and battery lifetime estimating means for estimating a lifetime of the battery on the basis of the terminal voltage of the capacitor at a time point when a predetermined time has passed from the start of charging of the capacitor.