PURPOSE: To obtain a growth film of high quality and high precision without damaging a substrate even in the case of large diameter, by installing a retaining stand which levitates and retains the semiconductor substrate from the rear, by using the pressure of gas which is introduced from a gas introducing part and passes apertures.

CONSTITUTION: Atmosphere gas of a reaction furnace is introduced from a gas introducing inlet 4 by a specified pressure. The gas is guided through a gas introducing furnace 3 and reaches a cavity part 5, in which the gas is horizontally dispersed. By the effect of pressure, the gas is jetted out upward via holes formed in the bottom surface of a recessed part 6. This atmosphere gas is blown against the rear of a semiconductor substrate 1 loosely engaged with the recessed part 6. Thereby the substrate 1 is levitated from the bottom surface of the recessed part 6 in the range from several μm to several tens of μm. The substrate 1 is retained in a non-contact manner with the peripheral part. At this time, the introduction pressure of the atmosphere gas is suitably adjusted in the manner in which the semiconductor substrate 1 is levitated from the bottom surface of the recessed part 6.