POLISHING APPARATUS

A polishing apparatus that can improve an accuracy of position coordinates associated with a measured value of film thickness is disclosed. The polishing apparatus includes: a pad-thickness measuring device configured to measure a thickness of the polishing pad; an optical film-thickness measuring device configured to emit light obliquely to the substrate, and determine measured values of film thickness at measurement points; and a controller configured to associates the measured values of the film thickness with measurement coordinates indicating positions of the measurement points. The controller is configured to determine amount of movement of the measurement coordinates corresponding to a measured value of the thickness of the polishing pad based on correlation data indicating a relationship between the thickness of the polishing pad and the amount of movement of the measurement coordinates; and correct the measurement coordinates associated with the measured values of the film thickness based on the determined amount of movement of the measurement coordinates.