An injection molding device includes a barrel, an injection screw, and an injection driving unit, wherein the injection screw includes a screw body, a screw head coupled to a front end of the screw body, and a check ring coupled to the screw head, the check ring including an accommodation groove that accommodates a portion of the screw head, a front member disposed in front of the screw head accommodated in the accommodation groove, and an accommodation member connected to the front member and surrounding a side surface of the at least a portion of the screw head accommodated in the accommodation groove, and when the injection screw moves forward to supply a molding material in the barrel to a clamping device, as the front member is pushed by the molding material accumulated on a front side of the injection screw, the check ring moves rearward from the screw head.