A manufacturing method for a semiconductor device, that loads a substrate on which a film containing oxygen atoms, chlorine atoms, and metal atoms is formed into a processing chamber so as to be supported by a substrate support part. The substrate is heated by the substrate support part. The inside of the processing chamber is exhausted by a gas exhaust part while supplying nitrogen atoms-containing gas and hydorgen atoms-containing gas into the processing chamber by a gas supply part. A plasma generation part is then used to excite the nitrogen atoms-containing gas and the hydrogen atoms-containing gas supplied into the processing chamber.