A polishing apparatus which can allow easy replacement of a retainer ring and can allow the retainer ring to be secured to a drive ring without causing deformation of the retainer ring is disclosed. The polishing head includes a head body having a substrate contact surface, a drive ring coupled to the head body, and a retainer ring surrounding the substrate contact surface and coupled to the drive ring. A first screw thread is formed on the drive ring, a second screw thread, which engages with the first screw thread, is formed on the retainer ring. The second screw thread extends in a circumferential direction of the retainer ring.