To provide a method for forming a film which can improve the degree of freedom of designing a substrate to be cleaned by cleaning only a desired part, and for stabilizing a film formation by stabilizing the substrate state before the film formation.

The method for forming the film comprises the steps of guiding fine particles generated from a fine particle generating chamber into a fine particle film forming chamber by utilizing a pressure difference between the generating chamber and the forming chamber and forming the film on the object to be formed disposed in the forming chamber. The method comprises simultaneously blowing the fine particles of the substance having sublimability and the fine particles of a film forming material to the object to be formed into the film, and thereby simultaneously cleaning by a sublimable substance and forming the film of the film forming material.