A polishing apparatus having a polishing pad surface property measuring device that is capable of measuring surface properties of a polishing pad in a state where a liquid film exists on the polishing pad is disclosed. The polishing apparatus includes a dam configured to dam a liquid on the polishing pad to form a liquid film having a thickness equal to or greater than a prescribed value in at least part of an area on the polishing pad, a light emitter having a light emission end disposed in the liquid film formed by the dam and configured to emit a laser beam onto the polishing pad, a light receiver disposed in the liquid film formed by the dam and configured to receive light scattered by and bounced off the polishing pad at a plurality of angles due to surface properties of the polishing pad after the laser beam is emitted from the light emitter, and a processor configured to perform Fourier transform on the light received by the light receiver into a predetermined wavelength corresponding to a reflection intensity distribution and to determine a feature quantity of the surface properties of the pad.