Abstract: The main feature of the present invention is to provide a reaction chamber for a chemical vapor deposition apparatus improved to achieve a uniform film deposition of high accuracy stably. The apparatus includes a wafer heating stage 28 for holding a wafer 14 with the surface downwards and for heating the wafer 14. The wafer heating stage 28 rotates about the center of the stage. In a low position opposing the wafer heating stage 28, a gas supplying head 37 is provided so as to form a constant spacing region 53 for supplying reaction gas towards the wafer heating stage 28. The reaction chamber includes a reaction chamber forming member 54 surrounding in a circumferential direction the spacing region 53 between the wafer heating stage 28 and the gas supplying head 37 to establish a reaction chamber having the spacing region 53 closed.