PURPOSE: To uniformly grow single crystal on a substrate having a large area using a compact type device by a method wherein the title device is constituted in such a manner that an organic metal gas discharging source can be scanningly moved against the substrate on which the single crystal will be grown.

CONSTITUTION: A GaAs substrate 11 having a large area is attached to the substrate holder 19, to be used for a large area, which is fixed to a vacuum chamber 1. Organic gas 7W9 is released to the substrate 11 from the organic metal gas releasing nozzles 13W15 fixed to the movable stage 12 which can be shifted two-dimensionally against the substrate 11. The released gas 7W9 is thermally decomposed on the substrate 11, it is grown in the form of an n-type GaAs single crystal on the substrate 11. As the ratio of each organic metal gas can be made uniform on the plane by scanningly moving the stage 12 against the substrate 11, the uniformity of the grown crystal can be accomplished.