Abstract: Upper parallelogram links (8, 8, 5, 12) and lower parallelogram links (14, 14, 12, 17) are series connected at an intermediate driving unit 12 with direction of the journal shafts (7, 7, 10, 10) of the upper parallelogram links and direction of the journal shafts (13, 13, 16, 16) of the lower parallelogram links being perpendicular to each other; thereby a third driving unit 17, to which a shaft of a hand 19 is mounted, is always kept in parallel to a first driving unit 5 irrespective of the position of the hand 19; thus a reliable handling by hand is assured, and also accurate horizontal motions are attainable with conventional computing means.