Foreign object detection device

A foreign object detection device comprising:

• a set sensor coil;
• and
• a determination device that detects a foreign object, based on a voltage of the set sensor coil,
• wherein the set sensor coil includes at least one sensor coil group,
• the at least one sensor coil group includes, electrically connected in series:
• a plurality of unit sensor coils that are wound in a first winding direction;
• and a plurality of unit sensor coils that are wound in a second winding direction,
• the plurality of unit sensor coils that are wound in the first winding direction generate a first-sign electromotive force that causes a current to flow in a first direction in response to a change in an external magnetic field in which magnetic field distribution is uniform,
• the plurality of unit sensor coils that are wound in the second winding direction generate a second-sign electromotive force that causes a current to flow in a second direction opposite to the first direction in response to the change in the external magnetic field,
• each of the plurality of unit sensor coils has a coil conductor that prescribes an external shape of the unit sensor coil, and
• a plurality of the coil conductors included in the at least one sensor coil group are continuously and electrically connected in series, and a part or a whole of the coil conductor forming the unit sensor coil wound in the first winding direction is a part or a whole of the coil conductor forming the unit sensor coil wound in the second winding direction.