PURPOSE: To provide a wafer polishing device and a method for dressing a polishing surface, with which dull of a polish cloth and surface unevenness are removed certainly and the quality of wafer is enhanced.

CONSTITUTION: The method includes a separating means 4 to separate a head 2 from the grinding surface 5a and a dressing pad 21 to be put in pressure contact with the grinding surface 5a when the head 2 is separated from the surface 5a, and thereby the grinding of wafer and the dressing works are conducted independently, and the ground surface of the wafer is prevented from ill affection of the falling objects such as abrasive grains off from the dressing pad 21 owing the dressing works.