High-Speed motion of linkage produces undesirable dynamic characteristics, such as fluctuation of input torque, shaking force and shaking moment. Therefore, various kinds of dynamic balancing have been proposed. In this paper, mass, position of center of gravity and moment of inertia of links are used as design parameters for dynamic optimization of the linkage. An algorithm to forming the shapes of links from these parameters is proposed. In order to prevent from getting unrealizable parameters an index of difficulty is proposed, too. The proposed method is applied to spatial RSSR mechanism' It is confirmed that the proposed method is effective.