The proposal in the study is an improved analytical method resulted from the modification of the conventional curve fitting method which is regarded as a strong mean to determine the physical factors related to the behaviors of carriers involved in the analytical process of thermally stimulated current characteristics observed on material, and the nomenclature of which is designated as "Optimal curve fitting" method. The test material selected in the study is polyvinylidene fluoride which is regarded recently as the excellent pyro- and pyro- electric polymer, and the selected peaky for the purpose of present investigation are restricted to those of two complex relaxation peaks observed one at low temperature side and title other at high temperature side. Those peaks can be decomposed into many individual single relaxation peaks by means of thermal cleaning method and numerical computation is carried out for obtained individual single peaks by adapting "Optimal curve fitting" method. In the process of numerical computation it is theoretically possible to obtain such physical factors as the magnitude and the temperature of peak, relaxation time, activation energy and depth of traps, those of which are related to the characteristics concerned. Furthermore, by the use of those theoritical values, the original complex peak is possibly reproducible with a fine precission in the all temperature range observed. Accordingly this fact is regarded as the evidence of a strong reliability of the proposed "Optimal curve fitting" method to adopt for practical use.