Heat treatment apparatus

A heat treatment apparatus for a semiconductor substrate, in which heat treatment can be performed at 1600 to 1900° C. by temperature control using a resistance heating element and a thermocouple thermometer, wherein:

• the resistance heating element and the thermocouple thermometer include a common constituent metal as a main component,
• the resistance heating element includes a plurality of bent plate type metal heating elements,
• each metal heating element includes two to four continuous side surfaces, and
• the side surfaces collectively form an approximately tubular polygonal shape in cross section in which a periphery of the approximately tubular polygonal shape includes the plurality of metal heating elements disposed with a gap between adjacent metal heating elements and in the cross section each metal heating element includes two to four bent planes.