A film forming process comprising introducing gas for forming a film from an inlet part for gas into a pressure-reducible deposition chamber wherein a substrate for forming a film thereon is supported by a fixing member, at least one of said substrate and fixing member are used so as to act as a first electrode, at least one portion of the wall of said deposition chamber is employed so as to act as a second electrode, the surface of said second electrode is arranged substantially in parallel to the surface for forming a film thereon, of said substrate, and said inlet part for gas and an outlet part for gas are arranged substantially in the positional relationship of rotation symmetry; and generating a glow discharge in said deposition chamber, thereby forming a film on said substrate.