Foreign matter detection device

A foreign matter detection device includes: a plurality of detection coils (43-1 to 43-n) between a transmission coil (12) of a power transmission device (2) and a reception coil (21) of a power reception device (3), through which power is transmitted in a contactless manner; a plurality of capacitors (44-1 to 44-n) forming, for each of the detection coils, a resonance circuit together with the detection coil; a power supply circuit (41) supplying AC power having a predetermined frequency to each detection coil; and a detection circuit (45) detecting a voltage output from each detection coil and detecting a foreign matter entering between the transmission coil (12) and the reception coil (21) according to the voltage detected. Then, each detection coil is arranged to overlap by a predetermined amount that allows electromagnetic coupling between adjacent two of the detection coils (43-1 to 43-n) to be ignored.