Both a magnetic recording width and a magnetic reproduction width of a magnetic head are equal to or larger than a combined width of a track width of tracks and double an off-track width of the magnetic head with respect to tracks on a magnetic recording medium during recording and reproduction of recording data, and are equal to or smaller than a width produced by subtracting double the off-track width during recording and reproduction from a combined width of the track width and double a groove width of grooves on the magnetic recording medium.