A wireless power transfer system includes a power receiving device and a plurality of power transmission devices that perform power transfer to the power receiving device. The power receiving device transmits request-power to the power transmission device, the request-power being power the power receiving device requests to be supplied with. The power transmission device, when receiving the request-power from the power receiving device, generates determination reference information based on the received request-power, the determination reference information being information to be used as a determination reference when the power receiving device selects the power transmission device, and transmits the generated determination reference information to the power receiving device. The power receiving device receives the determination reference information, selects the power transmission device from which the power receiving device is to receive power supply, and transmits a power transmission start request to the selected power transmission device.