To smoothly rotate an eccentric wheel for adjustment in time of a change of programming, even if a slight clearance change occurs by a temperature rise.

The shaft 11 of a rotator 10 is composed in a three-stage in radial direction and, the two intermediate wheels 32 and 33 are supported on a frame 13 on the circumference with a quartet race bearing 30 which is an eccentric wheel different in wall thickness. In this constitution, a rolling part is formed in a gap between the frame 13 and the intermediate wheels 32 and 33 or the eccentric wheel of the quartet race bearing 30 adjusting the rotation.