To provide a polishing device capable of more highly flattening the surface of a semiconductor wafer.

When the surface of a silicon wafer 14 is polished, the surface to be polished of the silicon wafer 14 is surface-polished by means of a polishing cloth 13 by rotating and revolving a polishing head 12 on a polishing surface table 11, on the upper face of which the polishing cloth 13 is unfolded and tensely spread, while a polishing fluid is supplied. In this case, since the surface temperature of the polishing cloth 13 is almost equalized, the reaction rate (polishing speed) on the slidably-contact surface between the surface of the polishing cloth 13 and the silicon wafer 14 becomes uniform. Thus, the polishing by abrasive grains of the polishing fluid becomes almost uniform over the entire surface of the silicon wafer 14, and thus the surface of the silicon wafer 14 can be more highly flattened.