PURPOSE: To work a groove which is stable in shape and size, and has high accuracy so that it can be mass-produced, by pressing a working roll against the inside circumferential face for forming a bearing face or the outside circumferential face of a shaft, and rolling it linearly and relatively against said circumferential face along the axial direction.

CONSTITUTION: A shaft 3 to be worked is fitted to a main shaft device 2, and the shaft 3 is supported and fixed by adjusting a position of supporting rolls 4,.... Subsequently, by adjusting a position of a working table 6, a working roll 17 is positioned at a position corresponding to one end of grooves to be formed 25,.... Thereafter, a bearing body 16 is lowered by a hydraulic cylinder device 18, and the roll 17 is brought into contact with the shaft 3. Subsequently, a prescribed distance table 6 is moved in the direction as indicated with an arrow 8, and a shallow groove 25 is formed. Next, the shaft 3 is rotated by a prescribed angle by the device 2, and the groove 25 is formed again as mentioned above. After one rotation, the same working is performed again by increasing the pressure of the device 18, and the groove 25 having a shape and size as prescribed is formed.