An object is to provide a power storage device provided with a battery that is a power storage means, for safe and accurate supply of electric power in a short period of time for drive power supply voltage without checking remaining capacity of the battery or changing batteries with deterioration over time of the battery for drive power supply voltage. The power storage device is provided with a battery that is a power storage means as a power supply for supplying electric power and a counter circuit for counting charging time of the power storage means. An electromagnetic wave with electric field intensity, magnetic field intensity, and power flux density per unit time which are transmitted from a power feeder are controlled, and the power storage means is efficiently charged using the electromagnetic wave in a short period of time.