To provide a plasma process apparatus which can manufacture a substrate where a film of high quality is formed and a manufacturing method for a thin-film formed substrate using the apparatus.

The plasma process apparatus which performs a plasma process for the substrate has a process chamber 10 internally having a substrate holder 40 holding the processed substrate 50, a gas intake 20 for introducing gas into the process chamber 10, and an electrode substrate 30 which is provided in the process chamber 10 opposite the substrate holder 40 and an anode 32b and a cathode 32, and an insulation part 34 insulating the anode 32b and cathode 32b. The surface of the electrode substrate 30 on the side of the substrate holder 40 has a plurality of surfaces including a slanted surface to a processed surface 50a of the processed substrate 50 and the plurality of surfaces are at angles which are not acute to adjacent surfaces.