PURPOSE: To manufacture a dental filling of excellent quality by preventing melted castable ceramics from being cooled during casting.

CONSTITUTION: A core pipe 14 is provided at approximately the center of a melting furnace main body 11 and a crucible 15 is enclosed in the core pipe 1 with its upper end portion projecting from the upper surface portion of the melting furnace main body 11. A heating resistance 16 is wound around the core pipe 14. A heating resistance 25 for raising the temperature of the upper end portion including the opening of the crucible 15 is wound around a recessed portion 24 provided at approximately the center of a cover 21 to enclose the upper end portion of the crucible 15. The heating resistance 25 is connected to a power source portion via a temperature regulator. A thermocouple 26 for detecting the temperature inside the cover 21 is disposed near the heating resistance 25. The thermocouple 26 is connected to the temperature regulator at one end so that detection signals can be transmitted. The melting furnace main body 11 thus formed and the cover 21 are connected to each other by means of a closing arm 28.