A charge control device uses external electricity to charge a plurality of battery devices. A constant current source uses the external electricity to generate and adjust an output current amount to a constant target value. A selector selects one battery device from the plurality of battery devices and supplies output current from the constant current source to the one battery device. A measurer measures an amount of actual current flowing from the constant current source to the one battery device. An instructor monitors a measured value provided by the measurer and instructs the selector, when the measured value meets a condition for a reduction of charging current amount to be regarded as having occurred, to change a destination to which the output current of the constant current source is supplied from the one battery device to a different battery device.