a drive unit for a vertical venetian blind includes a shared driving element for the displacing motion and the rotating motion of vertical slats . a differential gear is provided with a driving element coupled to the shared driving element , a first driven element coupled to the first drive means for the rotating motion of the vertical slats , and a second driven element coupled to second drive means for the displacing motion of the vertical slats . displacing motions and rotating motions of the vertical slats can be driven by the shared driving element . a complete closing of the vertical slats is made possible in both directions of rotation and , at the same time , a hooking up of the vertical slats by means of displacing same in an unsuitable rotating position is prevented .