Head load pressure generation means 36 is provided that flexibly supports an upper read/write head 25, via a leaf spring 27 attached to a main body 22, that moves forward and backward along the tracks on a magnetic data recording medium 3, and that adjusts the head load pressure applied to the upper read/write head 25 in accordance with whether a high-density or a low-density magnetic data recording medium is employed. Using this means, the head load pressure and the revolutions of a chucking motor are adjusted in accordance with whether a high-density or a low-density magnetic data recording medium is employed.