An actuation device for a slat, a rail for guiding and moving the slat into and out of an aircraft wing has the slat pivoted on the rail in a particular point (8); a thrust rod has one end hinged to the slat and a drive crank is connected to a second end of the thrust rod; a lever assembly connects the rail additionally to the slat at points on the rail and the slat different from the particular point and for pivoting and steering the slat relative to the particular point, for holding the rear end of the slat against the wing in a first protraction range and opening a gap upon further protraction.