A pole-layer-encasing layer made of a nonmagnetic material is disposed on an underlying layer made of a nonmagnetic conductive material. The encasing layer has a groove that penetrates. A pole layer is disposed in the groove. The pole layer is formed by plating through feeding a current to the underlying layer. A polishing stopper layer made of a nonmagnetic conductive material is disposed on the top surface of the encasing layer. The polishing stopper layer indicates the level at which polishing for controlling the thickness of the pole layer is stopped. The polishing stopper layer has an opening that penetrates, and the edge of the opening is located directly above the edge of the groove located in the top surface of the encasing layer.