<p>A rotary head device has a taper portion which is formed on an outer face at a lower portion of a rotary drum. The taper portion has a substantially conical shape which has a diameter decreasing as progressing toward a stationary drum. When the width of a magnetic tape is A, the length of the taper portion along the rotation axis direction of the rotary drum and between the start point of the taper portion on the outer face of the rotary drum and the lower end face of the rotary drum is B, and the depth of the taper portion along the radial direction of the rotary drum is C, the following conditions are satisfied: A/30 </= B </= A/7, and B/100 </= C </= B/20.</p>
