PURPOSE: To suppress the abrasion of a magnetic head by rotating a rotary cylinder at a regular recording and reproducing speed in the transfer time of a signal between the magnetic head and a magnetic tape and rotating the rotary cylinder faster than the regular recording and reproducing speed in a time other than the transfer time of the signal.

CONSTITUTION: When the signal is given and received between a magnetic head 1 and a magnetic tape 2, a rotary cylinder 3 is rotated in the direction of arrow head 13 at a regular speed by a rotation speed controller. At such a time, air is discharged from an air discharging groove 10 by the rotation of the rotary cylinder 3 and the size, the number and the form of the air discharging groove 10 are set so that the quantity of the discharged air can secure the transfer of the signal between the magnetic head 1 and the magnetic tape 2. On the other hand, when the signal is not transferred, the discharging quantity of the air from the air discharging groove 10 is increased with increasing the rotation speed of the rotary cylinder 3 faster, and the magnetic tape 2 is allowed not to contact with the head chip 101 of the magnetic head 1 while floating the magnetic tape or a contacting area is extremely reduced. Thus, the abrasion of the head chip is reduced.