To achieve weight reduction in a machine having a joint and a speed increase in operation by reduction in inertia moment, by an easily controllable noninterfering mechanism using a wire.

Pulleys 1 and 2 having a diameter of the reciprocal ratio of the bending angle ratio are arranged on two being shafts so that a change in the arc length with winding of the wire 6 becomes equal to the joint 3 bending in the same direction over two stages in the specific bending angle ratio. The wire 6 is inserted in an X shape, and when bending the joint, since the length of the wire 6 loosened from one pulley is wound on the other pulley, there is no change in the delivery length of the wire 6, and driving of the joint 3 and driving of the wire 6 do not interfere in driving force and displacement.