A power supply system supplies power from a plurality of vehicles to an external electrical apparatus. When power is supplied, the plurality of vehicles can select one of a generated-power supply mode, in which an engine is driven and a charged-power supply mode in which the engine is not driven. The power supply system includes a control unit that controls power to be supplied from the plurality of vehicles and, when power is supplied to the electrical apparatus, performs control so that the charged-power supply mode is selected for at least one of the plurality of vehicles that are power supply sources.