A soft magnetic core is substantially cylindrical and a linear-shaped coil conductor is inserted through a hole in the central portion of the soft magnetic core. A hard magnetic material sheet has areas which are magnetized in a thickness direction thereof and the areas are arranged in strips so that a magnetization direction of adjacent strips is mutually opposite. The hard magnetic material is wound on the outside surface of the soft magnetic core and is fixed to the soft magnetic core. The direction of the areas formed as strips of the hard magnetic material is substantially perpendicular to the axial direction of the coil conductor.