A polishing pad shape measured by a polishing pad shape measuring apparatus is modified into a target shape of a polishing pad by using a dressing tool so that a wafer has a desired surface shape. The invention is a method for shape modification of a polishing pad 14 for polishing a workpiece into a desired surface shape, comprising: a measurement step S9 of measuring a polishing pad shape in a state of being attached to a plate 12 by using a polishing pad shape measuring apparatus 10; a condition determination step S10 of selecting a dressing recipe capable of polishing the workpiece into a desired surface shape from a plurality of pre-provided dressing recipes based on the measurement result in the measurement step S9; and a shape modification step S11 of dressing the polishing pad 14 by using the dressing recipe determined in the condition determination step S10.