A power-receiving device includes a secondary-side coil which can receive a first alternating current power without contact from a power-sending device having a primary side coil into which first alternating current power is input. The power-receiving device comprises a first power transmission path, a second power transmission path, a common path positioned in common with the first and second power transmission paths, and a voltage regulator arranged on the common path. The voltage regulator rectifies the first alternating current power received by the secondary coil or the second alternating current power from a connecting portion, converts the rectified power to a predetermined specific voltage value, and outputs the power.