FOREIGN OBJECT DETECTOR

A foreign object detector includes multiple detection coils located between a transmitter coil in a transmitter device and a receiver coil in a receiver device to be electromagnetically coupled to one another, multiple capacitors each forming a resonant circuit together with a corresponding detection coil of the detection coils, a power supply circuit that supplies alternating current power having a predetermined frequency to each of the detection coils through a feeder coil located to be electromagnetically coupled to each of the detection coils, and a detection circuit that detects a voltage output from each of the detection coils and detects a foreign object between the transmitter coil and the receiver coil based on the detected voltage. The transmitter device transmits power to the receiver device contactlessly.