A power supply system includes a main power storage device and a plurality of sub power storage devices. A converter is connected to selected one of the sub power storage devices to convert voltage between the selected sub power storage device and an electric power feeding line bidirectionally. When the travel mode of an electrically powered vehicle is an EV mode, switching processing of a sub power storage device is performed based on the selected sub power storage device's SOC. On the other hand, when the travel mode of the electrically powered vehicle is an HV mode, control under which the SOC of the main power storage device and the plurality of sub power storage devices as a whole is kept constant is carried out, and switching of the selected sub power storage device is prohibited.