To make a film to be polished on a wafer have a constant film thickness during high-speed polishing even if a polishing pad has variance in thickness.

A novel polishing pad 13 is set on a rotary platen 14 of a CMP device. Then the thickness of the new polishing pad 13 is measured. The measurement result is input to a polishing control unit 19. Then the polishing control unit 19 determines a threshold corresponding to the thickness of the novel polishing pad 13 by reference to a data table 19b. Further, the threshold which is thus found is registered. Then the wafer 11 to be polished is polished using the threshold. Specifically, the wafer 11 is polished fast until the output of an eddy current sensor reaches the threshold, the high-speed polishing is switched to low-speed polishing once the threshold is reached, and the polishing is ended once a polishing end point is detected.