In a robot having at least one rotating joint (which may have at least two degrees of freedom), in order to perform a high-speed switching operation between a closed link mode and an open link mode with the outside world or a working object, each limb is provided with minimum-required, passive degrees-of-freedom (such as a backlash of a reducer) for removing a dynamic closing error and also the movable range of the limb is properly controlled. Even when an actuator for driving the corresponding joint has no means for obtaining a torque signal, a high-speed switching operation between the closed link mode and the open link mode can be stably achieved.