Polishing apparatus

The polishing apparatus is capable of precisely controlling polishing pressure, correctly positioning a press plate and uniformly polishing a workpiece. In the polishing apparatus, a holding head comprises: first pressing means for introducing a pressurized fluid into a first fluid chamber and pressing a main head section downward; second pressing means for introducing a pressurized fluid into a second fluid chamber and pressing a press plate downward; and third pressing means for introducing a pressurized fluid into a third fluid chamber and pressing the workpiece downward. With this structure, the workpiece is held on the lower side of an elastic sheet member, and the lower face of the workpiece can be polished by a polishing plate.