PURPOSE: To reduce the damage of a magnetic tape by reducing the contact resistance between a magnetic head and the magnetic tape, reducing the generation of fine vibration of the magnetic tape by a head chip protruding from the outer periphery of a rotary cylinder, and preventing the wear of a magnetic head.

CONSTITUTION: Head chips 4a and 4b are mounted opposinly while they protrude from a rotary cylinder by an amount of protrusion A. A rotary cylinder 1 has an outer-periphery part 7 in a shape where the radius of the rotary cylinder 1 gradually increases from R to R+amount of protrusion A from an outermost periphery part 5a at the front in rotary direction of the head chip 4a to an outermost periphery part 6a at the rear in rotary direction of a head chip 4b. Similarly, it has an outer-periphery part 8 in the same shape as that of the outer-periphery part 7 from an outermost periphery part 5b which is positioned at the front in rotary direction of the head chip 4b to the outermost periphery part 6a which is positioned at the rear in rotary direction of the head chip 4a.