FOREIGN SUBSTANCE DETECTION DEVICE, ELECTRICITY TRANSMISSION DEVICE, ELECTRICITY RECEPTION DEVICE, AND ELECTRIC POWER TRANSMISSION SYSTEM

A foreign object detection device includes a detection coil unit including a detection coil substrate () and a plurality of coils (), which are mounted on a surface of the detection coil substrate () and each include a conductive pattern turned around the Z axis, and a detector () connected to the coils () to detect the existence of a foreign object on the basis of a vibration signal output when each of the coils () is excited. The coils () each define an opening. The detection coil substrate () has a through hole () extending through the detection coil substrate (), and a component space for accommodating a switch () or a wiring pattern (), within each of the openings of the coils () as seen in the Z-axis direction.