Linear actuator comprising a reversible electric motor (20), a transmission (21), a non-self-locking spindle (22), where the reversible electric motor (20) through the transmission (21) drives the non-self-locking spindle (22) and a spindle nut (23) on the spindle (22). The actuator further comprises an adjustment element (24) secured against rotation and where the adjustment element (24) can be moved axially, as it is connected to or integrated with the spindle nut (23) on the spindle (22). Further, that actuator comprises position means for determining the position of the spindle nut (23), brake means for controlling the speed of the spindle nut (23) under the external load. Between the brake means and the spindle there is a coupling in connection with the position means for determining the position of the spindle nut (23). The coupling engages the brake means to the spindle or disengages the brake means from the spindle, when the spindle nut (23) is in a predetermined position on the spindle (22).