THERMAL TREATMENT APPARATUS

PURPOSE:To reduce the difference in heating history between processed bodies and shorten a recovery time by incorporating a heating source into a heat insulating supporter to largely secure the ratio of a flat zone length to a heater length. CONSTITUTION:A heat insulating material 40 is housed in the second hollow section 34 of a heat reserving barrel 30. A built-in heater 42 is placed in such a way that it is buried in this heat insulating material 40. In a stand-by state in which the heat reserving barrel 30 is outside a process tube 10, the built-in heater 42 is driven by a low power. Thereafter, a power consumption is gradually made to rise when a boat 22 is loaded, and a heating temperature by built-in heater 42 is set higher. Thus, the ratio of a flat zone length to a heater length can be secured large. The difference in the heating history is between processed bodies placed in the end side of a container can be decreased. In addition, a recovery time required for a temperature inside a furnace to return to a uniform temperature at processing time can be shortened.