A polishing method enables to initiation a second polishing step of a workpiece with an optimal thickness of an uppermost-layer film to be polished. The polishing method comprises: measuring a thickness of an uppermost-layer film, and then carrying out a first polishing step to polish the uppermost-layer film partway and a second polishing step to polish the remaining uppermost-layer film and a next-layer film; determining the polishing rates of the uppermost-layer film in the first and second polishing steps; and measuring a thickness of an uppermost-layer film of a predetermined nth workpiece and setting a processing time for the first polishing step of the nth workpiece or a next predetermined nth workpiece.