PURPOSE: To easily mold an item with a complicated shape in a short time without developing the clogging of resin by a method wherein a material mixing device is provided at the outlet of a port to feed material to a mold and the mold is hermetically closed and at the same time a vacuumizing device to evacuate the interior of the mold is connected to the mold.

CONSTITUTION: Resin, which is fed in a cylinder 13, is passed through a flow path 13-1 and fed from a material feeding outlet 13a at the tip part of the cylinder 13 to a mold 19. On the other hand, polymerizing agent is passed through a flow path 13-2 and fed from material feeding outlet 13b at the tip part of the cylinder 13 to the mold 19. The air in the mold 19 is withdrawn in advance by means of a vacuum pump. In addition, the resin and the polymerizing agent are mixed with each other by means of a mixing blade 11 when they are fed from the material feeding outlets 13a and 13b in the mold 19 and, after that, fed in the mold 19, which is held under vacuum. As a result, since no air mixed in molding material, a highly accurate molded item can be produced. Further, since no resin fixes to the material feeding outlets 13a and 13b and the like, every time when one molding cycle comes to an end, the mold 19 can be removed from the tip part of the cylinder and a new mold can be attached for next molding, resulting in allowing to efficiently perform a highly accurate molding.