Simultaneous thermogravimetry-differential thermal analysis/differential scanning calorimetry (TG-DTA/DSC) is the method with which changes in both the mass and energy of a sample upon heating can be measured simultaneously. From the data obtained, macromolecular information with regard to physicochemical change in the sample can be obtained. However, in order to know what specific kind of reaction takes place, information from other analytical methods is indispensable. For example, when the TG-DTA measurement indicates that an endothermic reaction accompanied by a mass loss takes place, this may suggest that one or more of a number of possible reactions occur, such as dehydration, evaporation, sublimation, decomposition, and reduction. In this case, if the structural formula, decomposition temperature, and content ratio of the absorbed moisture of the sample is available, it would be possible to suggest the kind of reactions that might be taking place. However, if the sample is totally unknown, even supposition is difficult. In this case, if information about structural change to the sample and the chemical species volatized were available from other analytical methods combined with the TG-DTA results, this would help understand the reaction processes taking place in the sample.