PURPOSE: To improve flatness by forming a pressurized room between an upper plate and a pressure plate fastened on the lower edge of an upper shaft and by providing a middle pressing shaft connected to the central part of the pressure plate and to displace the central part toward a carrier plate free to approach and separate on the upper shaft.

CONSTITUTION: A polishing cloth is attached on the upper surface of a turn table 80, and a carrier plate 81 with a wafer 82 to polish adhered on it is placed on it. At the time to start working, a cylinder device 85 pushes down an upper part housing 11, an integrated pressure plate 40 is lowered through a pressurized room 50a to maintain an upper shaft 10 and an upper plate 30 at specified pressure during polishing and makes contact with the carrier plate 81. By rotation of the turn table 80, a drive motor independently rotates and rotates the upper shaft 10, the upper plate 30, a bellows 50 and the pressure plate 40 integrally. When a slight curve with its top on its bottom is generated in the central part of the turn table 80 by heat generation, a central pressing shaft 70 pressurizes the pressure plate 40, pulls it up and corrects it. At the time of finishing polishing, respective rotation is stopped, the upper shaft 10 is lifted up in reverse to the initial and the carrier plate is separated.