PURPOSE: To reduce a machining time by forming grooves through a laser beam machining process in the case of a radial shaft in which a plurality of V-shaped grooves are arranged in parallel, being pined in an annular shape along the outer peripheral surface of a round shaft.

CONSTITUTION: When a plurality of V-shaped fluid holding grooves 3 are arranged in parallel in the peripheral direction on the rotational peripheral surface 2 of a shaft 1, laser beam machining is employed. That is, the V-shaped fluid holding grooves 3 are formed by operating the shaft 1 supported on a motor solid plate 11 by means of combination of the rotation of a motor 9, the movement of a movable table 10, and the laser beam convergence on the shaft 1 faced by a laser transmitter 5, full reflection mirror 7, and a condenser lens 8.