A thin film magnetic head is described, the magnetic head having an insulating layer and a protrusion which has an upper portion and a base portion, and the upper portion has an extended portion. The insulating layer is present under the extending part. A method of manufacturing the magnetic head includes forming a first insulating layer around the lower core layer; simultaneously forming a coil layer by plating the lower core layer with a coil insulating underlayer interposed between the lower coil layer and a coil lead layer connected to the coil layer on the first insulating layer; forming a coil insulating layer of an inorganic material on the coil layer and the coil lead layer; and, simultaneously forming a first plating underlayer for forming an upper core layer by plating, a second plating underlayer on the first coil lead layer exposed through the plating-forming opening, and a current-carrying lead layer.