While data that indicate a relationship between a dressing position P defined by a distance between a rotating shaft 11 of a polishing pad 13 and a rotating shaft 31 of a dresser 30 and shape change of the polishing pad 13 based on input of a target shape of the polishing pad 13 and alternating repetition of dressing the polishing pad 13 by the dresser 30 and measurement of shape of the polishing pad 13 by a pad shape measurement instrument 20 is acquired at a stage prior to commencement of a series of polishing steps for continuously polishing a plurality of polishing target objects (semiconductor wafer W) by a polishing tool 10, the polishing pad 13 is machined to the target shape 13 while the dressing position P is controlled, whereby the dressing position P is set during the polishing steps on the basis of a processing result of this data.