In one embodiment, a magnetic write/read device comprising a magnetic read element and a magnetic write element is formed in a thin film magnetic head portion of a magnetic head slider. A heat generating resistor is formed between a substrate portion and the magnetic reproducing device for heating thereby thermally expanding and protruding a portion of the magnetic head slider to control the flying height. The heat generating resistor is positioned between the substrate portion and the magnetic reproducing device being apart from the magnetic reproducing device for making the response speed for the flying height control of the magnetic head slider as high as possible and decreasing the effect caused by the heat generation of the heat generating resistor on the magnetic reproducing device as little as possible. The thickness of the insulating film is made greater than 10 times or less that of the heat generating resistor for ensuring insulation between the heat generating resistor and the metal film of a lower shield film.