To prevent the power supply efficiency of an inductor used in a DC-DC converter from declining, and to attain further size reduction and lower the profile, while maintaining a current which can be supplied.

In place of a coil that is to be wound, two or more conductors 14 penetrating the region between respective legs of an inductor core 11 without being wound are provided, and a current is fed thereto. Since the overall length of the conductor 14 is shorter, as compared with that of the coil, DC resistance in the circuit can be reduced. When a permanent magnet 15 that brings about the effects of magnetic bias is formed in the inductor core 11, improvement in the saturation magnetic flux density of the inductor core 11 is realized by the magnetic bias and size reduction and lowering of the profile of the inductor is effected.