A magnetic tape which is run at a speed of 4 m/sec. or higher and has recording tracks with a width of 21 .mu.m or less, and which includes a non-magnetic support, at least one magnetic layer formed on one surface of the non-magnetic support, and a backcoat layer formed on the other surface of the non-magnetic support, wherein servo signals for controlling tracking are recorded on the magnetic layer or the backcoat layer, the value of (.alpha./W).times.(V/f) is 10 [s.sup.-1] or less, and/or the value of (.alpha./W) is 0.1 or less, wherein V [mm/sec.] is a tape-running speed is; .alpha. [.mu.m] is an amount of a weave with a cycle of f [mm] on one edge of the tape or the other edge thereof as the reference side for the running of the tape; and W [.mu.m] is a width of the recording track. The magnetic tape can decrease PES and off-track and thus is excellent in servo tracking performance.