A composite (combined type of) transformer includes: a transformer core including a plurality of transformer magnetic leg portions, a transformer magnetic leg portion, and a pair of transformer bases; a plurality of inductor cores each including an inductor magnetic leg portions, inductor outer magnetic leg portions, and a pair of inductor bases; and a plurality of windings wound around the transformer magnetic leg portion and the inductor magnetic leg portions. The windings are wound to generate magnetic fluxes in such directions as to be cancelled out in a magnetic closed circuit in the transformer core.