PURPOSE: To keep evenly the thickness of growth films in the horizontal direction in a growth chamber by a method wherein solution tanks are respectively formed being adjacent to the sidewalls of the growth chamber formed in a boat for growth.

CONSTITUTION: Solvent tanks 12 and 12 are respectively formed being adjacent to sidewalls 3a and 3a at both left and right ends of a growth chamber 3. Ga is respectively filled in the tanks 12 as solvents 13 and the tanks 12 are sealed. A crystal material is housed in a melt reservoir 8 in an upper member 6 and is heated up in an H2 atmosphere to melt the crystal material. At this time, the solvent (the Ga) 13 sealed in the tanks 12 are also molten and the left and right sidewalls 3a and 3a of the chamber 3 are brought into a state that they are warmed by the heat of the solutions 13. Then, an operating rod 5 is pushed to move a boat 2 for growth to the left side in the diagram, melt 7 in the reservoir 8 is made to fall within the chamber 3 through a melt falling port 9 and GaAs crystals are respectively grown on the surfaces of substrates 11, 11.... Thereby, growth films of an even thickness are respectively formed on the substrates 11, 11....