An object of the invention is to provide a plasma doping method excellent in the uniformity of concentration of impurities introduced into the surface of a sample and a plasma processing device capable of uniformly performing plasma processing of a sample.In a plasma doping device according to the invention, a vacuum chamber (1) is evacuated with a turbo-molecular pump (3) as an exhaust device via a exhaust port 11 while a predetermined gas is being introduced from a gas supply device (2) in order to maintain the inside of the vacuum chamber (1) to a predetermined pressure with a pressure regulating valve (4). A high-frequency power of 13.56 MHz is supplied by a high-frequency power source (5) to a coil (8) provided in the vicinity of a dielectric window (7) opposed to a sample electrode (6) to generate inductive-coupling plasma in the vacuum chamber (1). A high-frequency power source (10) for supplying a high-frequency power to the sample electrode (6) is provided. Uniformity of processing is enhanced by driving a gate shutter (18) and covering a through gate (16).