A linear actuator includes a jacket defining an axis and a rod having an end cylinder tightly slidable in the jacket and an opposite end sliding between a rest position and a working position. The end cylinder divides the jacket into a first and a second variable volume compartments fluidly independent from each other, one of them being fluidly insulated and under vacuum, the other one being fluidly communicating with the outside environment. Upon the passage of the opposite end of the rod from the rest position to the working position, one of the variable volume compartments passes from a minimum volume to a maximum volume, in order to suck the rod and automatically recall the opposite end from the working position to the rest position.