A thermal analysis apparatus possesses a support base, a heating furnace which is approximately like a cylinder, and whose inside can be raised in its temperature, till a predetermined heating temperature, a heating furnace fixation part fixing the heating furnace to the support base, a furnace tube which is approximately like the cylinder, inserted through the heating furnace while having an interstice, and has been fixed in its base end part to the support base by a fixation member, a fixation means which makes the furnace tube capable of expanding or contracting in an axial direction, and positioning-fixes it in a radial direction, a sample holding means which holds a sample in an inside of a heating part of the furnace tube, that is a range capable of being heated by the heating furnace, and a temperature measurement means measuring a temperature change of the sample.