To provide a magnetic tape that can meet the requirement for high-density recording and reduce damages to the tape by suppressing the meandering run of the tape in actual use.

By running a 12.65mm wide magnetic tape 1 along the reference run surface S and keeping the tape edge 4a at the reference position T applying a tape tension of 0.65N to 0.75N, the tape is inclined by 1.5 degree that is β by an inclined guide 5 to the reference run surface S and wound around the inclined guide 5 by 60 degrees that is α. A measuring instrument 6 positioned near the inclined guide 5 measures the misregistration H of the tape which is the distance from the reference position T to the lower tape edge 4a to obtain the amplitude of the curve of the tape edge 4a. The amplitude of the curve measured in this condition shows that the magnetic tape 1 runs with a displacement of 0μm to 30μm all through its length.