PURPOSE: To improve the polishing precision and improve the polishing work efficiency by providing a dresser with a correcting ring correcting a polishing fabric on the outer periphery of a top ring.

CONSTITUTION: A dresser 15 is freely rotated independently from the rotation of a top ring when a turntable is rotated for polishing, a correcting ring 17 is brought into contact with an abrasive fabric, thus the roughness on the surface of the abrasive fabric can be corrected concurrently with the polishing of a wafer. The correcting ring 17 is located on the outer periphery of the top ring, and the whole surface of the abrasive fabric can be set to the uniform state along the peripheral direction of the turntable in a circle slightly larger than the polishing region of the wafer. The abrasive fabric is corrected on the surface when it enters the correcting ring 17, it is brought into contact with the wafer after being corrected, thus the polishing precision can be sharply improved.