This report describes a new method to deduce temperatures in concrete after fire. In this paper, the temperatures in fire-damaged concrete members were presumed, aiming at admixture responsive to thermal career. By measuring the ultraviolet absorption spectra of admixture, it was found that heated temperatures in concrete were possible to be presumed from absorbances. At the next stage of this study, heated temperatures in actually fire-damaged concrete were presumed by using this method. Moreover, the validity of this presumption method was verified by comparing the presumed temperatures with the actually measured ones in the firetested concrete members(f1oor and column). The influence of burning exhaust on this presumption method was also examined and it was found that there was no influence of the exhaust on the method by shaving off the surface layer of concrete.