The invention relates to an actuator of an electrohydraulic gas exchange valve drive of an internal combustion engine, comprising an actuator housing (4), which can be fixed in the internal combustion engine and which comprises a bore (9); a valve play compensation element (8) which is received in said bore in an axially movable manner and which comprises a compensating housing (12) for actuating the gas exchange valve (1); and an axial stop which limits the extending movement of the compensation housing out of the bore (9) and which comprises stopes (14, 15) that overlap each other radially. The stop (14) on the compensation housing-side is a collar of a sleeve (18) that surrounds the outer casing of the compensation housing said collar extending outwards in a radial manner.