To provide a new casting method with which a material impossible to be cast with the conventional technique can be cast.

Molten metal 42, such as molten magnesium alloy containing calcium, is stuck on the inner surface 22 of a cavity by drawing up from the molten metal while applying ultrasonic vibration to an upper mold 20. Successively, powdery additive 52 (aluminum powder, etc.), is brought into contact with the molten metal 42 stuck on the inner surface 22 of the cavity. In this way, the additive 52 is caught on the inner surface 22 of the cavity. The caught additive 52 is fused while applying the ultrasonic vibration to the upper mold 20 and also, mixed with the molten metal 42. In such a way, mixed molten metal of the fused additive 52 and the molten metal 42 is adjusted on the inner surface 22 of the cavity. Thereafter, the upper mold 20 and a lower mold are mated and the mixed molten metal is closed into a casting space formed with this mold mating and cooled and solidified.