To assist human motion in the fields of rehabilitation and sports training, we propose a passive motion support system consisting of wires with servo brakes and a control method to guide the human hand. However, passive systems sometimes cannot generate enough force to guide the human hand along the desired path because the servo brakes cannot generate a driving force and the system does not have enough brake units to generate the desired force. In this paper, we theoretically consider the feasible braking force region of a passive system with multiple brake units and discuss the number of brake units required to generate the desired force appropriately. We also develop a system based on our analysis of the feasible braking force and conduct path-following experiments. The experimental results illustrate the validity of a passive motion support system consisting of wires with servo brakes.