The relationship between polishing conditions constituting elements and the worked shape (amount of polishing) obtained by means of these polishing conditions is input beforehand into polishing condition determining means along with the type of the object of polishing, and polishing conditions (invariable polishing conditions) that are used in common for the polishing of this object of polishing. The polishing condition determining means determine the polishing conditions on the basis of these conditions. Specifically, the above-mentioned polishing conditions constituting elements are given in a time series, or combinations of the above-mentioned polishing conditions constituting elements are converted into variations in the swinging velocity of the polishing body, and the swinging velocity corresponding to the swinging position is determined. The polishing apparatus control means input the polishing conditions determined by the polishing condition determining means, and control the polishing apparatus so that these polishing conditions are realized. As a result, working conditions for obtaining a specified worked shape in a working apparatus can be simply and accurately determined.