A thin film magnetic recording head comprises a substrate, a first magnetic core formed on the substrate, a second magnetic core having the front end face with a magnetic gap with respect to the front end face of the first magnetic core, and a coil for developing magnetic flux between the front end portions of the magnetic cores. A width of the second magnetic core at the front end portion thereof is chosen to be smaller than that of the first magnetic core. The second magnetic core is at a leading position relative to the second magnetic core in a traveling direction on a recording medium. In such configuration, it is possible to reduce side erase due to recording magnetic flux fringing and to achieve high density of magnetic recording while maintaining the conventional fabrication steps for the thin film magnetic recording head, thereby avoiding the problem in the fabrication.