A metal melting furnace which effectively melts a melting material and holds the temperature of the molten material to reduce fuel. The metal melting furnace has a material charging port and a flue at its top and a melting chamber with a heating plate which melts a melting material charged from the material charging port at its bottom. A heating burner is disposed at a bottom side of the heating plate of the melting chamber and is used to melt the melting material on the heating plate. Exhaust gas of the heating burner, which circulates through the exhaust gas channel, is used to preheat the melting material of the flue. At a bottom side of the heating burner of the melting chamber, a molten material holding section into which molten material flows to be stored is formed. The heating burner holds the temperature of the molten material.