PURPOSE: To obtain an apparatus with which the film thickness and the composition of an epitaxial film can be made uniform by a method wherein at least end parts of gas introduction tubes are formed in a concentric and conical shape which is expanded to the side of a substrate and in which several end parts are overlapped.

CONSTITUTION: In a metal organic vapor growth apparatus, the following are provided: a support stand 2 on which a substrate 3 has been placed inside a reaction tube 1; several gas introduction tubes used to introduce a raw-material gas for growth use and a carrier gas into the reaction tube 1; and several mass-flow controllers 14 to 16 which are connected to the gas introduction tubes and which adjust the composition, the concentration and the flow velocity of the raw-material gas for growth use. In the apparatus, at least end parts of said gas introduction tubes are formed in a concentric and conical shape which is expanded to the side of the substrate 3 and in which several end parts are overlapped. For example, a concentric and conical gas injector 20 constituted by overlapping three kinds of cones 20a to 20c which are concentric and whose diameter is different is installed. Thereby, the gas can be blown uniformly to the whole surface of the substrate, and a convection current can be suppressed. As a result, the uniformity of the film thickness and composition of an epitaxial film can be enhanced.