An articulated robot comprises one or more articulation angles that can assume two states on the occasion of the same position or attitude of an object being controlled. A change from one to the other of the above described two states is taught by operating an operation panel and the respective driving means of two arms constituting one articulation angle are controlled based on the above described teaching information so that the articulation angle may be changed from one state to the other state, whereby rotation of the respective arms is controlled.