In a thin film deposition apparatus, means for depositing a film on a substrate and means for etching the deposited film to make flat the surface thereof, are provided in a reaction vessel independently of each other. This apparatus can rapidly deposit the film without rising the temperature of the substrate excessively. Further, since the deposition means and etching means are independent of each other, the deposition of a film on the substrate and the planarization of the surface of the deposited film can be achieved under various conditions.