A thin film magnetic head wherein a partial insulating layer is formed on a bottom pole layer with a gap layer provided therebetween, the gap depth Gd being regulated by the distance from a surface facing a recording medium to the partial insulating layer. A magnetic flux partially leaks from a tip region of an upper core layer to the bottom pole layer through the partial insulating layer to effectively suppress magnetic saturation of the tip region, thereby improving the NLTS characteristic and PW50 characteristic, and suppressing the occurrence of side fringing.