To provide a metal melting apparatus whose holding amount of molten metal is quite small and a metallic ingot is easily melted into molten metal.

When the metallic ingot K preheated with a preheating device 20 is melted into molten metal with a heating material 14 by a local heating device 10 or a high frequency induction heating device, the melting amount is controlled with a control unit so that the molten metal amount in a holding furnace 40 is always kept constant with a molten metal amount sensor 42 disposed in the holding furnace. In this way, the necessary quantity of the molten metal to one time of forming cycle in a casting device supplied into an injection sleeve 52 is minimized in the holding furnace 40 by melting at each forming cycle.