A transmission antenna includes a transmission coil, and transmits an electric power signal. A driver applies a driving signal to the transmission antenna. A first temperature sensor measures the temperature of the transmission coil, and generates a first temperature signal. A second temperature sensor measures the temperature of an interface surface on which an electronic device mounting a wireless power receiving apparatus is to be placed, and generates a second temperature signal. A control circuit controls the electric power signal according to the difference between the first temperature signal S11 and the second temperature signal.