A clockwise helical groove is formed on the outer periphery surface of a
rigid roller toward one end from the center position in the axial
direction. A counter-clockwise helical groove is formed on the outer
periphery surface of the roller toward the other end from the center
position in the axial direction. The roller rotates, accompanied by a
magnetic tape. The clockwise groove of the roller gives a regulating
force, which points toward the center position, to the magnetic tape. The
counter-clockwise groove of the roller gives a second regulating force,
which points toward the center position, to the magnetic tape. The
magnetic tape is given the regulating forces simultaneously that point
toward the center position in the axial direction of the roller. The
magnetic tape is restrained from swinging to one end or the other end in
the axial direction of the roller, and the tape traveling becomes stable.