To provide a polishing device incorporating a wear monitoring means for its polishing pad and a control method for the same device, both providing a proper maintenance schedule of the polishing pad of the polishing device.

The polishing device incorporating a wear monitoring means for its polishing pad, together with the control method for the device, monitors the wear of the polishing pad at polishing with a process-integrated noncontact sensor 110, and changes its own operation parameters to compensate the uneven polishing caused by this way, or directs that the polishing pad be changed for another, depending on the obtained measured value. The sensor 110 moves across the polishing pad on the surface of a polishing belt 130 being rotated at a frequency integer-times as high as that of the rotation of the polishing pad, to follow a predetermined zigzag orbit on the polishing pad or monitor the abrasion loss of one point on the polishing pad continuously.