Abstract: Driving rollers 2, 3 which rotate in the same direction are arranged in parallel to each other. A plurality of convex portions 5a, 5b, 5c having different radii of curvature Rr1, Rr2 and Rr3 are formed along the axial direction at opposing positions on the driving rollers 2, 3. A rolling element 4 which is fed into the gap between the driving rollers 2, 3 and rotated is moved along tracks having different radii of curvature Rw1, Rw2 and Rw3 in the axial direction. There is provided a superfinishing grindstone 6 which is pressed on the rolling surface of the rolling element 4 moving on tracks having different radii of curvature to superfinish the rolling surface of the rolling element 4.