PURPOSE: To enable to securely seal a gate, by a method wherein a metallic mold provided with a forcibly cooling means at a part proximite to a gate introducing part provided with a restricted gate is used, a molten resin is charged under pressure into a cavity of the mold, and then the gate introducing part is locally solidified by cooling by the forcibly cooling means.

CONSTITUTION: In a metallic mold wherein a gate 5 and a sprue 6 are connected to each other by a narrow gate introducing part 7 constituting a restricted gate such as a runner having a length required for preventing to some extent the transmission of heat from a cavity 4, pipes 8, 8' for passing a cooling medium are provided at a part proximite to the gate introducing part 7 and spaced from the cavity 4 by a distance required for preventing the transmission of heat from the cavity 4. When a molten resin is charged into the cavity 4 of the metallic mold, the resin at the gate introducing part is rapidly solidified by cooling by the cooling means 8, 8'.