The invention concerns a safety device (1) for an actuator comprising a connection means (2) allowing a connection to a releasable holding means (5). The connection means (2) is fixed via a sacrificing means (3) to a supporting means (4), and a resilient means (7) is acting between the supporting means (4) and a supporting portion (8). An extension means (9) is fixed to the supporting means (4) via the connection means (2). The sacrificing means (3) has a mechanical strength such that the sacrificing means (3) breaks when subjected to a force exceeding a predetermined force, such that the extension means is no longer fixed to the supporting means and that a re-connection of the supporting means (4) and the releasable holding means (5) is made impossible. The predetermined force is lower than the mechanical strength of the extension means (9) and the supporting means (4). A linear actuator (13) comprising the safety device (1) is also provided.