On the development of gripping end-effector, it is important for the grippign endeffector to have not only a required gripping ability such as max gripping force and max gripping speed, but also cost-effectiveness. Robot hands have various gripping modes, however it needs many costs due to many degree of freedom with motors and sensors. On the other hand, the specific end-effector adapted to target process has relatively lower cost than robot hands. The end-effector with low degree of freedom and deformable jaws, it is possible to grip the various gripping target with various shape and stiffness. As a part of embodiment of the specific end-effector with deformable jaws, in this paper, we describe the parameter study for selecting optimal value of design variable with deformable jaws through structural analysis.