An encasing section includes an encasing layer having an encasing groove, and a nonmagnetic film disposed in the encasing groove at a position between the encasing layer and a pole layer. The pole layer includes a track width defining portion and a wide portion. The track width defining portion has a first side surface and a second side surface. The wide portion has a third side surface and a fourth side surface. The encasing layer has a first wall surface and a second wall surface. The distance between the third side surface and the first wall surface is smaller than the distance between the first side surface and the first wall surface. The distance between the fourth side surface and the second wall surface is smaller than the distance between the second side surface and the second wall surface.