Injection-molded part, and molding method and molding device therefor

The invention provides a high-quality injection-molded part capable of preventing weld lines, and a molding method and a molding device for molding the high-quality injection-molded part. The injection-molded part is a molded part (lens) (2) molded into a shape that is long in at least one direction, in the lens (2), a plurality of gate marks (24) are present along the longitudinal direction thereof, and the cross-sectional area of a first gate mark (24 (G1)) present in the center of the injection-molded part in the longitudinal direction is larger than the cross-sectional area of second gate marks (24 (G2)) present on both sides thereof. Furthermore, a third gate mark (24 (G3)) may be present on each of the outer sides of the second gate mark (24 (G2)) in the longitudinal direction, and the cross-sectional area of the third gate mark (24 (G3)) is larger than the cross-sectional area of the second gate mark (24 (G2)). 本发明提供防止熔接线产生的高品质的注射成形件、以及成形高品质的注射成形件的成形方法和成形装置。该注射成形件是成形为至少在一个方向上较长的形状的成形件(透镜)(2)，在透镜(2)中，沿着