Abstract: An electrically operated driving shaft control device includes a casing having a driving shaft vertically journalled therein and a driving means for rotating it. A movable plate member has a first end with an upward projecting plate and a bearing seat with two first oval-shaped openings on both sides. A second plate provided on the movable plate has a first end distal from the projecting plate and a second end fixed in the casing. The second plate has a second oval-shaped opening and two threaded hole on both sides of the oval-shaped opening. The driving shaft has one end connected to the driving means and another end passing through the bearing seat of the movable plate member and the second oval-shaped opening of the second plate. A guiding roller is fixed to the driving shaft on the second plate. A rope encircles the guiding roller and connects to a blind. A means for breaking an electric circuit when a predetermined tension of the rope is reached during rotation of the driving shaft.