PURPOSE: A high vacuum die-casting method is provided to efficiently discharge the internal gas of a cavity while molten metal is injected into the cavity where a metal product is molded. 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 is vacuumed from the cavity and is discharged to the outside through a first path. Gas is vacuumed from a sealed space and is discharged to the outside through a second path. Eject pins (50) push a metal product from the movable mold.