PURPOSE: To inject resins without any mixing of resins constituting individual layers in sandwich molding and prevent webbing at a bottom part of a molded article, by a method wherein a plurality of main bodies of hot runner nozzles are simultaneously moved by a movable plate, sealing positions of the nozzles are corrected by a hydraulic piston, and a sealing position of a gate-sealing pin is also corrected by a spring.

CONSTITUTION: In a notched part 3a of a hot nozzle storing plate 3 fixed to a fixed-side fitting plate 2 of a fixed platen 1, the movable plate 4 is reciprocated by a pair of hydraulic cylinders 6. A cavity plate 7 holding a female mold 27 is fixed to the plate 3. A male mold 19 is fixed to the first movable mold plate 11. The nozzles 40, 41 are communicated with an internal hole 29 provided in the main body 28 of the hot runner nozzle through resin passages 42, 43. The gate- sealing pin 32 capable of being reciprocated by engaging with an engaging piece 31a of the hydraulic piston 31 closes a tip part of the internal hole of the nozzle 30, and securely seal the gate provided in the main body 28 under energizing by the spring 39.