To realize the stable sliding load, to transmit the torque in a state of high rigidity, while surely preventing the rattling in the rotating direction, to improve the durability and to reduce the manufacturing cost.

A spherical body 7 rolling when a male shaft 1 and a female shaft 2 are axially relatively moved, is mounted between a plurality of pairs of axial grooves formed on an outer peripheral face of the male shaft 1 and an inner peripheral face of the female shaft 2, and an installation angular pattern of the axial groove 3 of the outer peripheral face of the male shaft 1 and an installation angular pattern of the axial groove 5 of the inner peripheral face of the female shaft 2 are different from each other.