To surely control the temperature of a substrate by adjusting the parameters of a heat-treatment gas, that is supplied to the substrate in accordance with a prescribed heat treatment period for adjusting the temperature of the substrate and causing relative rotation of the substrate and a gas supply system.

A substrate support body 16 is rotated at an appropriate speed. Then, while a relatively hot gas and a relatively cold gas are supplied from a heat has source 34 and a cold gas source 36 to a substrate 2 via a gas supply system 18 by a control device 32, while controlling the flow rate, mixing ratio, and temperature, thus obtaining a desired substrate temperature distribution over a long time. Also, the substrate support body 16 may be fixed and the gas supply system 18 may be rotated, thus uniformly controlling the temperature of the substrate 22 by relatively rotating the substrate support body 16 and the gas supply system 18. Also, nonuniformity caused by swelling, shrinkage, or the like of the plate is eliminated, since gas is used as compared with a case where the substrate 22 as a whole is brought into contact with the hot or cold plate as in prior art.