To provide a CMP polishing device for polishing a large bore wafer without increasing a device size, etc., and having high working efficiency and plane accuracy.

A wafer 1 is mounted on the upper surface of a turn table 3, and three abrasive heads 4a-4c are arranged in the upper part of the table 3. The heads each are mounted with polishing cloth at the lower surface, rotationally driven, and also given reciprocating motion in the radius direction of the table 3. The polishing heads each have the same diameter, and are arranged so as to have distance from the center of the table 3 at regular intervals in the reference position in the reciprocating motion, moreover are arranged so as to cover closely all portions in the radius direction from the center to outer peripheral part of the wafer. The speed of the reciprocating motion of each head is set so as to gradually become a lower speed with the shift from the head positioned on the center side of the table 3 to the head positioned on the outer peripheral side.