In a power supplying side core around which a power supplying side resonant coil is wound that contactlessly supplies power to a power receiving side resonant coil, a pair of protrusion portions is provided that protrudes from central axis direction both sides of the power supplying side resonant coil toward the power receiving side resonant coil. Further, in a power receiving side core around which the power receiving side resonant coil is wound that contactlessly receives power from the power supplying side resonant coil, a pair of protrusion portions is provided that protrudes from central axis direction both sides of the power receiving side resonant coil toward the power supplying side resonant coil.