The thickness dependency of the temperature image obtained by an infrared thermography was investigated using specimens with three kinds of metal materials of different heat conduction and four kinds of thickness of the specimens. Then, the infrared hybrid method was developed to separate each stress components. However, it contains the influence of heat conduction in the infrared stress measurement method. Therefore, heat conduction error will arise in the infrared hybrid analysis. Then, the new system which corrects the error by an heat conduction inverse analysis was developed. Thereby, the accuracy of the stress intensity factor was able to be raised using heat conduction inverse analysis. Furthermore, the accuracy of hybrid method taking heat conduction into consideration was discussed in comparison with 3-D finite-element analysis and the 2-D infrared hybrid method.