A regulating device for the linear regulation of an actuating element is connected for movement to a ball spindle drive for the conversion of a rotational movement into a linear movement. The rotational movement can be transferred to the spindle drive from at least one motor via a gear unit. The gear unit exhibits a self-locking, helically toothed spur-wheel gear, which is formed as a double helical gear with at least one first and second spiral-toothed gearwheel. In each case at least one motor is arranged at both ends of the ball spindle drive and each motor is connected for movement with a second spiral-toothed gearwheel.