PURPOSE: To prevent the generation of shrinkage cavities in die cast products by providing a level difference of a bore larger than the inside diameter of an injection sleeve in the part near the joint surfaces of an injection chamber, and providing a riser pressurizing device in a riser molten metal chamber.

CONSTITUTION: A level difference 16 of a bore larger than the inside diameter of an injection sleeve 9 is provided in the part near the joint surfaces of an injection chamber 15, and molten metal is packed into a cavity 3 through a flow divider 18, a runner 17 and a gate 20. On the other hand, a riser pressurizing device consisting of a riser pressurizing plunger 22, a spring 23, and a spring bracket 24 is provided in a riser molten metal chamber 21. All the parts to be in contact with molten metal are beforehand coated with a heat insulating material. When themolten metal is injected into the cavity 3 by the plunger 11, the molten metal in the chamber 15 maintains fluidity and is kept pressurized by the plunger 11 until the molten metal in the cavity 3 solidifies thoroughly, whilist a riser pressurizing plunger 22 also pressurizes the molten metal. Thereby, the solidification is accomplished without generation of shrinkage cavities in the molten metal.