The thermal analyzer comprises temperature deviation approximation formula holder which holds an approximate formula of a temperature deviation between sample and furnace and an elevating or lowering rate of the temperature of furnace during measuring the temperature deviation, programmed temperature corrector which corrects a programmed temperature in proportion to the elevating or lowering rate of the temperature. So that, since the temperature deviation is corrected in proportion to the elevating or lowering rate of the temperature program, the temperature deviation between sample and furnace is controlled to diminish when heating or cooling the sample using the temperature program which elevates or lowers the temperature of the sample or the furnace.