To provide a crucible furnace for using a metal crucible at high temperatures not lower than 1,000°C, in which atmosphere in the vicinity of the crucible during the time of the high temperature is controlled, the temperature control in the crucible can be made precise, and the life of the crucible is made long.

The crucible furnace for processing a compound in the metal crucible 4 at the high temperatures not lower than 1,000°C is characterized in that the first sleeve 1 comprising a detachable heat resistant thin dense ceramics is placed around the metal crucible 4, and the second sleeve 2 comprising an insulation material and a heating device 3 is placed outside of the first sleeve 1.