A polishing apparatus polishes a substrate by moving the substrate and a polishing pad relative to each other. The apparatus includes: an elastic modulus measuring device configured to measure an elastic modulus of the polishing pad, and a polishing condition adjustor configured to adjust polishing conditions of the substrate based on a measured value of the elastic modulus. The polishing conditions include pressure of a retaining ring, arranged around the substrate, exerted on the polishing pad and a temperature of the polishing pad.