PURPOSE: To realize the stable transfer of a tape and to reduce the wow and flutter of an apparatus by preventing the whirling of the upper end of a capstan shaft.

CONSTITUTION: The surface of a capstan shaft 24 coming into contact with a thrust bearing 25 is convex spherical surface and the surface of the thrust bearing 25 coming into contact with the capstan shaft 24 is also a concave spherical surface with a curvature almost equal to that of the convex spherical surface of the capstan shaft 24. Therefore, when the contact part P is in the position not coinciding with the bearing center, the x-axial component force Fx of a reaction force F is generated without fail to energize the capstan shaft 24 always to the bearing center so that even if the capstan shaft 24 bends by a magnetic unbalance between a permanent magnet 3 and a stator flat plate 4 or by the contact bonding force of a pinch roller 13, the whirling of the tip 24a of the capstan shaft 24 is controlled by the action of an energizing force Fx. As a result, the tip 24a is prevented from whirling.