The use of Computer Aided Engineering (CAE) for product development is more advantageous in reducing the development time cycle as well as reducing cost than the case of using hardware. However, a question is if the simulated results can be reproduced by hardware. In this study, the improvement of the rigidity of a structure without fabricating the hardware is reported. In the study, the rigidity of a structure was optimized using quality engineering and CGE. For the generic function, it was considered that the input (load) is proportional to the output (displacement) and zero-point proportional equation was used. The thicness of various dimensions was used and compounded as the noise factor. The standard SN ratio was calculated using the nominal amount of displacement as the signal. As a result, the collditions of improving the rigidity were determined and the reproducibility was confrmed. Moreover,the concentrated stress in the structure before study became dispersed after optimization. The study was completed in a short period of time at a low cost compared with the one using hardware.