A pole layer is disposed in a groove of a pole-layer-encasing layer made of a nonmagnetic material with a nonmagnetic film disposed between the encasing layer and the pole 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 a penetrating opening, and the edge of the opening is located directly above the edge of the groove located in the top surface of the encasing layer.