PURPOSE: To control the temperature stress of a mass concrete structure in which stress of the part where generation of a crack is estimated of placed concrete is moved to another lower stress part so as to enable to equalize stress distribution for settling stresses on all the parts within the allowable value by partial heating.

CONSTITUTION: When a rectangular concrete structure is placed, if similar temperature drop are generated in respective layers, tensile stress is generated due to restraint by a base rock-bed. At this time, it is presumed that tensile stress over the allowable stress is generated in the vicinity of the basic face. Then, heating process to add the prescribed temperature to the layer from the outward is performed. Thereat, a stress distribution is generated within the heated concrete layer, and unbalanced internal stress due to the temperature difference generated in concrete is redistributed so as to be diffused and equalized.