PURPOSE: To form a hetero epitaxial layer of small transition regions of carrier concentration and crystal composition in an interface by blowing off group V element containing gas to a formation substrate when a gas kind and a flow rate are switched and by sucking and removing the discharged gas when the switching is completed.

CONSTITUTION: A substrate 8 is made close to a blowoff port 13, and PH3 and H2, group V element, are blown off from the port 13 of a tubular member to be supplied to the substrate 8. Meanwhile, HC1 which is group III raw material transportation gas is supplied from a supply tube 3 of a lower reaction chamber 10, and PH3 and SiH4, n-type doping gas, are supplied from a supply tube 4 of the lower reaction chamber 10. When the gases supplied to the lower reaction chamber 10 are in steady-state, the substrate 8 is made close to the upper stream of a gas suction port 14 and PH3 and H2 gases are sucked by a suction port 14. Thereby, it is possible to eliminate influence of remaining epitaxial growth gas.