PURPOSE: A high vacuum die-casting method is provided to efficiently discharge the internal gas of a cavity while molten metal is injected in the cavity. CONSTITUTION: A high vacuum die-casting method is as follows. A movable mold (20) is attached to a fixed mold (10) to form a cavity. Molten metal is injected into a sleeve (30) through a molten metal inlet. A plunger in the sleeve moves to inject the molten metal of the sleeve into the cavity. Gas in the cavity is discharged to the outside through a first path during the injection of the molten metal. Gas in a sealed space is discharged to the outside through a second path during the injection of the molten metal. A metal product is pushed from the movable mold by eject pins (50).