INJECTION MOLDING DEVICE

PROBLEM TO BE SOLVED: To prevent orientation lines formed behind an opening-forming body facing a gate with respect to the resin-injecting direction, from being observable from the outside of the molded article to the utmost, even in the synthetic resin-molded article containing filler and having an opening.SOLUTION: When the injection volume of melted synthetic resin 30 from the gate 26A into a cavity 24 is increased, the orientation lines 27A2, 27B2 are formed behind the opening forming bodies 25A, 25B which face the gate 26A. Before pressure keeping is started after the orientation lines 27A2, 27B2 are generated, lifting pins 28A, 28B are returned to positions being flush with a cavity forming surface of a movable metal mold 23 after the lifting pins 28A, 28B enter into the cavity 24. During lifting, the orientation lines 27A2, 27B2 are obliquely deformed, a space S1 is formed in the synthetic resin 30 in the vicinity of the orientation lines 27A2, 27B2 by lowering, and the synthetic resin 30 in the vicinity of the orientation lines 27A2, 27B2 are pushed and led to flow so as to be buried in the space S1 by further injection of the synthetic resin 30 from the gate 26A.