A coil unit includes a coil formed of a conducting wire arranged on a first plane and laid side by side with itself in an inside-outside direction with a coil axis normal to the first plane as the center, and a plurality of magnetic plates arranged on a second plane which is along and adjacent to the first plane. A gap which is formed by the magnetic plates and traverses the inside-outside direction of the coil is located near an edge portion of the coil in the inside-outside direction.