The present invention is to provide a substrate holder which can effect a more complete sealing with a sealing member and makes it possible to take a substrate out of it easily and securely, and also a plating apparatus provided with the substrate holder. A substrate holder (18), includes: a fixed holding member (54) and a movable holding member (58) for holding a substrate (W) therebetween; a sealing member (68) mounted to the fixed holding member (54) or the movable holding member (58); and a suction pad (94) for attracting a back surface of the substrate (W) held between the fixed holding member (54) and the movable holding member (58).