PURPOSE: To form in one stage in the shape prior to the heat treatment by heating once by placing the heated aluminum block inside the grooved die of the lower die of a rotary forging machine and by pressurizing with rotating both the upper die and lower die.

CONSTITUTION: The upper die 2 of the rotary forging machine consisting of the lower die 1 to rotate on the horizontal face centering around avertical rotary shaft A and the upper die 2 which is made to rotate and move vertically centering around the rotary shaft B fixed with the inclination α against the rotary shaft A, is ascended. The aluminum block 4 heated to the prescribed temp. is fitted into the grooved die of the lower die 1 and the aluminum block 4 is pressurized by descending the upper die 2 with rotating both upper and lower dies and deformed along the gap formed between the upper and lower dies and the work is finished at the time of the guide parts 5 of the upper and lower dies being abutted. The forging article to form the shape prior to the heat treatment of an aluminum wheel is thus produced.