PURPOSE: To prevent the wear and head crash of a medium providing a displacement center to measure a distance between magnetic heads and an actuator to keep constantly the distance.

CONSTITUTION: An actuator 8 fitted at a magnetic head 4 is driven so as to keep constantly the distance while the distance between a medium 3 and a head 4 is measured by a displacement sensor 6, and the interval of the medium 3 and the head 4 is fine kept with non-contacting and a very light load. In order to prevent the contact of the edge surface of the head 4, the surface of the head 4 is made into the curved surface, simultaneously, it is deformed by the pressure of the head 4 to a substrate or the medium 3 by using the elastic body and a constant area of the spacing is widened. Thus, it is eliminated that the head 4 is inclined, the head edge surface is contacted with the medium, and the medium and head are destructed.