원래 이름 기록: MICRO ENGINEERING, INC.

Provided is a polishing head and a polishing treatment device that can cope with the wrinkle phenomenon, the star mark phenomenon and the like, further improve the SFOR or the like of the substrate surface and steadily perform a polishing treatment of a large number of substrates with high quality. A polishing headincludes a membrane support ringa membranethat covers a lower end-side opening part of the membrane support ringand holds a substrate W with a backing filmpasted to a front surface side thereof interposed therebetween, and a retainer ringshaped to accommodate the membrane support ringand surround the outer circumference of the substrate W. On the back surface side of the membranea plurality of radial ribsthat radially extend from the vicinity of the center of the membraneand a circular ribthat is shaped to have a size smaller than the size of the elastic body are formed, and the radial ribsare formed to radially extend outward from the circular ribIn a region defined by adjacent radial ribsthe membrane support ringand the circular ribon the back surface side of the elastic body, a rib lock membershaped to be in contact with the side surfaces of the adjacent radial ribsthe inner circumferential surface of the membrane support ringand the outer circumferential surface of the circular ribis arranged.