Each vehicle includes a detection device configured to detect a situation outside the vehicle. When a server receives from a depleted EV a help signal requesting power supply from another vehicle to the depleted EV, the server selects, from among the other vehicles, a rescue EV to supply electric power to the depleted EV. The rescue EV moves to the depleted EV, determines a stopping position of the rescue EV from a situation around the depleted EV detected by the detection device, and performs power supply to the depleted EV at the stopping position.