A charging controller (300) controls charging of a battery by an interface device (400-1 to 400-m) on the basis of distribution system connection time when the interface device (400-1 to 400-m) and a battery mounted on EV (500-1 to 500-n) are connected to each other and on the basis of distribution system disconnection time when they are disconnected in each of the interface devices (400-1 to 400-m).
