A workpiece holder for polishing comprising a workpiece holder body which is provided with multiple perforated holes for holding a workpiece by vacuum suction and a holder back plate which is closely contacted with a back face of the holder body and has grooves for vacuum, wherein the holder back plate is composed of a synthetic resin and has an Asker C hardness of 70 or higher but lower than 98, and an apparatus for polishing a workpiece and a method for polishing a workpiece utilizing it. By improving the material of holder back plate of a workpiece holder for polishing that holds a workpiece by vacuum suction to enhance sealing with the holder body, thereby developing such a holder back plate that should not transfer deformation of the holder body to the workpiece surface, even if polishing agent slurry is introduced and solidified, to provide a workpiece holder for polishing having a workpiece holding surface of high precision, an apparatus for polishing a workpiece and a method for polishing a workpiece.