A method of a polishing a wafer includes: a first polishing step of polishing a surface of the wafer while supplying a rough polishing liquid onto a polishing surface of a rough polishing cloth; subsequent to the first polishing step, a protection film formation step of supplying a protection film formation solution containing a water-soluble polymer to the rough polishing cloth after being used in the first polishing step and bringing the protection film formation solution into contact with the polished surface of the wafer to form a protection film on the polished surface; and a second polishing step of polishing the surface of the wafer where the protection film is formed while supplying a finish polishing liquid to a polishing surface of a finish polishing cloth different from the rough polishing cloth.