In the double-side polishing apparatus, one end part of a slurry supply hole has a female-tapered face whose inner diameter is gradually increased toward a polishing face of a polishing plate. A pad hole, which corresponds to the slurry supply hole, is formed in a polishing pad covering the slurry supply hole. An edge of the pad hole is located in the slurry supply hole. A fixation pipe, in which a flange section facing the female-tapered face is formed at one end part, is fixed in the slurry supply hole. The edge of the pad hole is sandwiched and held between the female-tapered face of the slurry supply hole and the flange section of the fixation pipe.