PURPOSE: To improve productivity and product quality by providing a projecting part to a stationary die so as to contact with the materials cast in runner parts and parting the product part and the runners and drawing the runners from the intermediate mold simultaneously by die opening force in the stage of opening dies.

CONSTITUTION: A molten alloy to be cast is charged into an injection chamber 78, main and auxiliary runners 80, 82, a gate 84 and a cavity 72, and is cooled to solidify and to shrink. Therefore, the alloy in the runner 80 part adheres tightly to the projecting part 86 of a stationary die 60 by enclosing the outside circumference thereof and is hardly detachable from the die 60. The cavity 72 is so formed that a product 96 clings to a moving die 64 as in an ordinary way. In the starting stage of die opening upon completion of cooling of the molten metal, the alloys in the runners 80, 82 are kept stuck tightly to the mold 60, and the alloys in the gate 84 and the cavity 72 move left together with the die 64 and an intermediate die 66. Thus the alloy in the gate 84 is parted by die opening force. When the die 64 moves left further, the die 66 is stopped; therefore the product 96 detaches from the die 66 and moves left while sticking on the die 64. Upon completion of die opening the product is ejected from the die 64, and the runners 80, 82 are ejected together with the alloy in the chamber 79 from the die 60.