A manufacturing method of a thin film magnetic head is provided. In the manufacturing method of a thin film magnetic head, an inorganic insulating layer is formed along at least a sidewall surface of each conductor part. A gap of each conductor part is filled by an organic insulating layer. An upper surface of the conductor part, a magnetic pole portion, and a connecting layer are grinded to be planar with an organic insulating layer and an inorganic insulating layer. During an upper surface of each conductor part is grinded, the inorganic insulating layer, which is hard, suppresses a shear drop of each conductor part by grinding.