PURPOSE: To stably travel a magnetic tape at a prescribed speed without using a tape transfer mechanism such as capstan and pinch roller systems.

CONSTITUTION: An index signal I is previously recorded on the lower end edge of the magnetic tape 1A at a tape manufacturing process. The tape device is provided with a frequency difference detecting means 19 for comparing the output of an index signal reproducing frequency detecting means 18 with the output of a reference signal generating means 20. A torque signal is generated by a reel speed and rotation control means based on the output of the frequency difference detecting means 19, and the torque signal is imparted to a supply reel driving means 11 and a takeup reel driving means 12. When a feedback control is executed so that the frequency difference may become zero in such a way, the transfer speed of the magnetic tape 1A is controlled so as to be kept constant.