For virtual usability evaluation of universal design, our previously-developed grasp synthesis method for human hand model was extended by employing soft finger model. Our previous method treated a hand model as a hard finger that assumes point contact with friction, which was not able to synthesize a grasp with two-point contact that often observed in the real world. Therefore, we incorporated the judgment of graspability based on the soft finger model and confirmed the synthesis of multiple types of plausible grasps including two-point contact through the simulation.