A polishing cloth is dressed between polishing processes each for polishing a workpiece such as a semiconductor wafer. The polishing cloth is dressed while supplying a dressing liquid such as water during a dressing process, and an abrasive liquid for polishing a workpiece is supplied to the polishing cloth for a predetermined period of time prior to a polishing process. The predetermined period of time may be present within the dressing process and immediately precedes the polishing process, and the dressing process may be carried out while supplying the abrasive liquid to the polishing cloth. Alternatively, the predetermined period of time may be present between the dressing process and the polishing process.