The present invention provides a method of manufacturing a thin film magnetic head capable of assuring recording characteristics by determining throat height with high precision. A TH specifying layer is formed so as to extend to a position P1 while being adjacent to a gap layer, and an auxiliary insulating layer is similarly formed so as to extend from the position P1 while being adjacent to the gap layer and specify throat height on the basis of the position P1. After that, a main insulating layer is formed so as to cover a thin film coil on the auxiliary insulating layer, and a yoke layer is formed so as to extend while being partially on the TH specifying layer. The throat height is determined accurately and stably on the basis of the position P1 by the auxiliary insulating layer.