meshing with said threaded sleeve 7 a power part of a control for the motor 9 is given reference number 9 a by means of rotation secured straight guidance of the threaded rod 6 in the housing 1 the threaded rod 6 is axially moved and urged against the rear of the piston under the action of the threaded rod 6 the piston 5 is moved to an ampoule outlet thereby displacing insulin through said ampoule outlet a fluid line 3 is connected to said ampoule outlet at the free front ends of which an infusion needle n is fixed which the user pierces under his skin and then fixes it on his skin so that he can self administer insulin further included in the fluid line 3 is a valve 4 likewise accommodated in the housing 1 which only enables insulin to flow when a minimum pressure given by said valve 4 is exceeded in said ampoule 2 a position sensor 14 measures the actual value of the angular position of the stepper motor 9 and transmits it via signal lines as the actual position p to a radio interface 13 and to an emergency control 11 provided in the housing 1 if run properly the emergency control 11 is driven in a stand by mode the emergency control 11 is connected to the position sensor 14 and the power element 9 a via signal lines it receives the actual position p from the position sensor 14 and transmits its adjusting signal c u2032 to the power element 9 a if the emergency control 11 has been activated to move the motor 9 to a subsequent desired position an.