A film forming method, for depositing a thin film on a surface of a substrate mounted on a mounting table disposed in a vacuum processing chamber, includes an adsorption process for adsorbing a film forming material on the substrate by introducing a source gas into the processing chamber; and a reaction process for carrying out a film forming reaction, after the adsorption process, by introducing an energy transfer gas into the processing chamber and supplying thermal energy to the film forming material adsorbed on the substrate. By repeating the above process, the thin film is formed on the substrate in a layer-by-layer manner.