PURPOSE: To reduce the carrier density of a grown layer by one figure or more without reducing growing speed by a method wherein reducing gas is introduced between a material region and a grown substrate using inert gas for conveyance of material gas.

CONSTITUTION: All carrier gas in the region of high temperature group III metallic material is formed into inert gas, and the reduction gas necessary for reaction of semiconductor growth is introduced on the up-stream of the growth region having the temperature lower than that of the above-mentioned metal material region. For example, when a semiconductor is grown by introducing hydrogen from a bypass in the amount of 30% of the total flowing quantity in the state wherein material 2 is heated up to 800°C, a substrate 4 at 700°C, and the density of hydrogen chloride and hydrogen phosphate is formed at 5000 ppm respectively, for example, the carrier density of the grown layer can be reduced to 2E15/cm2 which is 1/10 of 2E16/cm2 when hydrogen is used as the carrier gas of hydrogen chloride.