PURPOSE: To prevent contact between a tape and a cylinder and to ensure the stable travelling of the tape, by providing a groove at a minor diameter part of a taper-shape cylinder and fitting a tape control pin on or near the above-mentioned groove.

CONSTITUTION: A rotary cylinder 11 is formed into a taper shape, and a tape control pin 14 is fixed so as to keep a static state at the position of a groove 13 toward the minor diameter of the cylinder 11 and with no contact secured to the bottom part of the groove 13. A magnetic tape 12 wound round the cylinder 11 tries to displace toward the minor diameter owing to the taper shape of the cylinder 11, but this shift is prevented by the control pin 14. Thus the tape 12 can have a stable travel along a locus which is decided by the pin 14 and two limiter posts 17 and 18. At the same time, the air flows into the groove 13 with the rotation of the cylinder 11 to produce an air film of uniform thickness between the cylinder 11 and the tape 12. This prevents the flaws of the tape 12.