PURPOSE: To make it possible to change a tape speed easily only by changing the gradient of a triangular wave corresponding to the change in tape speed, by previously adjusting and setting a comparison voltage of a certain tape speed for every track corresponding to the skew.

CONSTITUTION: One triangular-wave generator 5 is provided and to this generator 5, write clock WCL is input. As for a triangular wave output from this generator 5, its gradient can be changed according to a tape speed. In addition, voltage comparing circuits 61, 62... are provided and they are supplied with the triangular wave from generator 5. Further, FF21, 22..., write head driving circuits, 31, 32..., and exciting coils 41, 42... are connected to respective voltage comparing circuits 61, 62.... Consequently, each skew adjustment is automatically made only by changing the gradient of the triangular wave according to the change in tape speed, and the tape speed can therefore be changed, so that the easiness to use will improve.