The polishing amount of an optical fiber component can be measured directly, accurately and easily in a real-time mode during polishing, regardless of the polishing amount of a ferrule. Provided is a method for measuring the polishing amount of an optical fiber component while performing polishing, the method including: branching an inspection light among a reference optical path having a variable optical path length, an optical fiber component being measured, and a comparison optical path, and determining a polishing amount of the optical fiber component by a change amount of a difference Lc between a reference optical path length when return light of the reference optical path interferes with return light of the optical fiber component being measured and a reference optical path length when the return light of the reference optical path interferes with return light of the comparison optical path.