nt in time when the lower shield layer 3 and the corresponding magnetic layer 303 have been formed, the boundary between the head area 101A and the planned area 101B is flat without any step between them.Then, an insulating layer 24 is formed on the head area 101A using an insulating material such as alumina (Al2O3) or the like, and a portion of the insulating layer 24 where the rear magnetic pole