The invention provides a foreign metal detection device that reduces the likelihood of failing to detect a foreign metal. The foreign metal detection device 14A is equipped with: a sensor unit S whichhas at least one antenna coil L3 that receives a magnetic field or electric current and generates a vibration signal Vb; a vibration time length measurement circuit 145 which measures the vibration time length TL, which expresses the length of time required by the vibration of a vibration signal Vc outputted by the sensor unit S and of a prescribed wavenumber greater than 1; and a determination circuit 146 for determining whether there is a foreign metal near the antenna coil L3, on the basis of the vibration time length TL, and a reference time length CTL, which is the vibration time lengthTL when there is not a foreign metal nearby.