PURPOSE: To improve operational efficiency by a method in which a check valve is inserted into an urethane-pouring hole, and then the inlet side of the check valve is connected to the feeding side, and its outlet side is connected to the side of an urethane-pouring hole, and next the resin in molten state is fed in a cavity through the check valve.

CONSTITUTION: A pouring nozzle 3 is connected to the urethane-pouring hole 15 of a wheel 9, and the head 16 of a pouring machine is connected to a check valve body 1, and then the urethane resin in molten state is poured into the check valve body 1 from the head 16. Accordingly, the resin flows to exit part 5 from the connected part 4 of the check valve body 1, thereby pushing down the valve body 2. Consequently, the valve body 2 blocks the upper end of the pouring port 7 of the pouring nozzle 3, but since a notch 6 is provided on the valve body 2, the resin enters the pouring port 7 through the notch part 6 and enters a cavity 12. When the resin is foamed by generating chemical reaction, the valve body 2, is raised by its pressure, thereby blocking the exit part 5 of the cheek valve body 1. Consequently operational efficiency is improved.