The invention relates to an actuating device, in particular for a vehicle braking system, having an actuating mechanism, a power-operated actuator, a first travel sensor for sensing the travel of the actuating mechanism, and having an evaluation unit, an additional travel sensor, which can be actuated separately from the first travel sensor, wherein the travel sensors are actuated by way of two elements which can be moved relative to each other and wherein the differential travels and/or differential forces of the travel sensors are measured and evaluated by the evaluation unit. According to the invention an actuating element (103a) is provided which is movably connected to one of the elements which can be moved relative to each other and is movably arranged with respect to the other movable element.