A magnetic recording/reproducing apparatus compares speed information obtained by speed detecting means for a magnetic tape with a set travelling speed of the magnetic tape in a control circuit, and controls the rotational frequency of a driving motor for a take-up reel, thereby controlling constant-speed travelling of the magnetic tape, with employment of no capstan. According to this system, the overall apparatus can be simplified and miniaturized with reduction in weight and cost. Further, it is possible to improve constant-speed travelling performance of the magnetic tape by adjusting resonance and antiresonance appearing due to total equivalent inertia moment related to the magnetic tape and reels in the transfer characteristic of the control system.