A charging system is provided herein. The charging system includes an alternating current (AC) power source, opening/closing rectifying units composed of rectifying circuits and opening/closing circuits, and a control device. The rectifying circuits are connected to modules formed by dividing a battery into the modules. The rectifying circuits supply direct current (DC) electric power obtained by rectifying AC electric power supplied from the AC power source to the modules. The opening/closing circuits switch between connection and disconnection between the AC power source and each of the modules. The control device controls connection and disconnection of the opening/closing circuits in accordance with a state quantity of at least one of an output voltage of the AC power source and an input voltage of the rectifying circuits or a state quantity associated with at least one of the output voltage and the input voltage.