To fully charge a battery by a multi-power-source battery charger either when a DC power having a voltage corresponding to the charging voltage of the battery is input or when a DC power having a voltage higher than the charging voltage of the battery is input, the supply destination of the input DC power is switched, in accordance with the voltage of the DC power input to the battery charger, between a controller which controls charging of the battery in accordance with the charging voltage of the battery and a DC/DC converter which controls the voltage and current of the DC power supplied to the battery through the controller.