The present invention efficiently radiates heat generated by a coil while suppressing a decrease in the efficiency of generation of magnetic fields caused by an eddy current. The present invention includes a coil extending spirally in a plane and covered with a dielectric material, a magnetic substance provided parallel with the plane so as to overlap the coil, and a radiator extending in the plane so as to surround the coil and having projecting portions which project toward an outermost periphery of the coil and groove portions recessed in a direction opposite to that in which the projecting portions project, the projecting portions and the groove portions being alternately arranged, the radiator having a higher thermal conductivity than the magnetic substance.