PURPOSE: To execute a uniform forming by combining and coupling a multi-layer urethane rubber from an urethane rubber having various outside diameters and hardnesses, and using it for forming a thin cylinder.

CONSTITUTION: A multi-layer urethane rubber 11 of one body is formed by coupling a cylindrical urethane rubber of 14W23 by an upper fixed seat 24 and a nut 25, and a lower fixed seat 13. As for the urethane rubbers 23, 14 of the upper and lower ends, the outside diameter is made small, and as for the multi- layer urethane rubber 11, the center part uses a softer rubber, and also, an urethan rubber of a strong hardness is used for the upper and lower parts. An outside metallic die 8 and an inside metallic die 9 are installed on a pedestal 7, a thin cylinder 10 is inserted, and subsequently, the multi-layer urethane rubber 11 is inserted and pressed by a press 12. The center part of the urethane rubber 11 is deformed easily, and a uniform forming can be executed.