A thin film magnetic head, in which: a magnetic gap thereof is disposed slantingly relative to a direction orthogonal to a scanning direction of the head corresponding to an azimuth angle; an upper magnetic core layer is positioned on a leading side preceding a lower magnetic core layer in a scanning direction of the head, a protrusion on the lower magnetic core layer has an inclined side surface inclined at an angle equal to or greater than the azimuth angle at least on one side surface in a direction of a track width thereof, and at least one edge of a side adjacent to the magnetic gap of a protrusion on the upper magnetic core layer is aligned on a line drawn extending from the inclined side surface of the lower magnetic core layer, thereby suppressing occurrence of side erasing in a magnetic recording medium during azimuth recording.