PURPOSE: To improve productivity by filling molten resin into another cavity unit while slow cooling one cavity unit in the gate sealed state, and also improve molding accuracy by retaining the given dwell pressure by means of a self-retaining mechanism and a gate sealing means.
CONSTITUTION: A plurality of cavity units 10, each of which consists of a couple of molds 11 and 12 and a self-retaining mechanism 15 for retaining the mold clamping force of the molds are provided. Said units are conveyed through a heating section 20, a filling and relaxing section 30, a slow cooling section 40 and a molded product releasing section 50 successively. A heating means 21, an injection filling means 60 disposed in the filling and releaxing section 30 and a sealing means for sealing a gate section of respective cavity units 10 are also provided. Further a cooling means 41 disposed on the slow cooling section 40 and a molded product releasing means for releasing a molded product cured in the molded product releasing section are provided.