A coil unit includes a planar coil, a coil-receiving housing having a depression that receives the planar coil, the planar coil being disposed in the coil-receiving housing so that a transmission side of the planar coil faces a bottom of the depression, and a substrate having a mounting surface that is provided with a mounted component and faces a non-transmission side of the planar coil, an inner end lead line and an outer end lead line of the planar coil being connected to the substrate. The substrate is secured as a lid of the coil-receiving housing on an open end side of the depression of the coil-receiving housing.