By a linear actuator of the type comprising a driven spindle with a spindle nut, the outer positions and possibly also the intermediate positions of the spindle nut can be determined by a specially designed switch construction. This switch comprises an elongated conductor (8a), and next to this at least one other short conductor (8b), and where a connection element (10) for the spindle nut is equipped with an electric conductive element (9), for creating contact between the two conductors (8a, 8b). With two short conductors at the end of the elongated conductor end-stop switches for the nut are achieved and with more short conductors between the two end conductors the position of the spindle nut between its outer positions can be determined.