A vehicle electric power supply system configured to supply electric power wirelessly to a vehicle that is positioned within an electric power supply area, comprising: a power-receiving device and a charging control unit that are provided in the vehicle; a plurality of power-transmitting devices (1a1, 1a2, 1a3, 1b1, 1b2, 1b3, 1c1, 1c2, 1c3) that are provided at mutually different positions within the electric power supply area; a control device configured to detect the position of the power-receiving device within the electric power supply area; wherein the vehicle is provided with a battery that is configured to store power that has been received by the power-receiving device; characterized in that: the control device is configured to first receive via wireless communication from the charging control unit the approximate position of the power-receiving device within the vehicle and to select, from among the plurality of power-transmitting devices (1a1, 1a2, 1a3, 1b1, 1b2, 1b3, 1c1, 1c2, lc3), the power-transmitting devices that are located in positions that are closest to the power-receiving device and supply power sequentially from the selected power-transmitting devices to the power-receiving device; and the control device is configured to further detect the position of the power-receiving device with respect to the selected power-transmitting devices based on the amount of charged power per unit time that is stored in the battery, and to cause power to be supplied wirelessly from the power-transmitting device, among the selected power-transmitting devices, which has the greatest charging efficiency of the amount of charged power per unit time. a power-receiving device and a charging control unit that are provided in the vehicle; a plurality of power-transmitting devices (1a1, 1a2, 1a3, 1b1, 1b2, 1b3, 1c1, 1c2, 1c3) that are provided at mutually different positions within the electric power supply area; a control device configured to detect the position of the power-receiving device within the electric power supply area; wherein the vehicle is provided with a battery that is configured to store power that has been received by the power-receiving device; characterized in that: the control device is configured to first receive via wireless communication from the charging control unit the approximate position of the power-receiving device within the vehicle and to select, from among the plurality of power-transmitting devices (1a1, 1a2, 1a3, 1b1, 1b2, 1b3, 1c1, 1c2, lc3), the power-transmitting devices that are located in positions that are closest to the power-receiving device and supply power sequentially from the selected power-transmitting devices to the power-receiving device; and the control device is configured to further detect the position of the power-receiving device with respect to the selected power-transmitting devices based on the amount of charged power per unit time that is stored in the battery, and to cause power to be supplied wirelessly from the power-transmitting device, among the selected power-transmitting devices, which has the greatest charging efficiency of the amount of charged power per unit time. the control device is configured to first receive via wireless communication from the charging control unit the approximate position of the power-receiving device within the vehicle and to select, from among the plurality of power-transmitting devices (1a1, 1a2, 1a3, 1b1, 1b2, 1b3, 1c1, 1c2, lc3), the power-transmitting devices that are located in positions that are closest to the power-receiving device and supply power sequentially from the selected power-transmitting devices to the power-receiving device; and the control device is configured to further detect the position of the power-receiving device with respect to the selected power-transmitting devices based on the amount of charged power per unit time that is stored in the battery, and to cause power to be supplied wirelessly from the power-transmitting device, among the selected power-transmitting devices, which has the greatest charging efficiency of the amount of charged power per unit time.