Linear electromechanical actuator, comprising: - a containment structure; - a pusher designed to translate relative to the containment structure in order to at least partially protrude from the containment structure during the actuator operation; - a mechanical reduction apparatus arranged in the containment structure and rotatable about a rotation axis; - drive means arranged in the containment structure and operatively connected to said mechanical reduction apparatus to rotate it about said rotation axis; - a shaft at least partially externally threaded extending between a first end connected to the pusher and an opposite second end, said shaft being fitted into said mechanical reduction apparatus and connected to said pusher, said shaft being mechanically connected to said mechanical reduction apparatus such that a rotation of said mechanical reduction apparatus determines a translation of the shaft along said rotation axis; - an anti-rotation mechanism active on said shaft to prevent the shaft from rotating about said rotation axis; said anti-rotation mechanism being arranged internally and/or externally to said containment structure; characterised in that said mechanical reduction apparatus comprises: - a nut having a thread pitch; - a longitudinal pushing element along said rotation axis, said nut and said longitudinal pushing element being independent of each other and rotatable about said rotation axis under the action of said drive means; said longitudinal pushing element being fitted into said nut; - coupling means (10, 11, 15, 16) configured to mechanically couple said nut and said longitudinal pushing element with said shaft, such that a rotation of said nut and/or of said longitudinal pushing element determines a translation of said shaft along said rotation axis; said coupling means (10, 11, 15) comprising: - an intermediate coupling stage interposed between the nut and the longitudinal pushing element, said shaft being at least partially fitted into said intermediate coupling stage and into said longitudinal pushing element. - a containment structure; - a pusher designed to translate relative to the containment structure in order to at least partially protrude from the containment structure during the actuator operation; - a mechanical reduction apparatus arranged in the containment structure and rotatable about a rotation axis; - drive means arranged in the containment structure and operatively connected to said mechanical reduction apparatus to rotate it about said rotation axis; - a shaft at least partially externally threaded extending between a first end connected to the pusher and an opposite second end, said shaft being fitted into said mechanical reduction apparatus and connected to said pusher, said shaft being mechanically connected to said mechanical reduction apparatus such that a rotation of said mechanical reduction apparatus determines a translation of the shaft along said rotation axis; - an anti-rotation mechanism active on said shaft to prevent the shaft from rotating about said rotation axis; said anti-rotation mechanism being arranged internally and/or externally to said containment structure; - a nut having a thread pitch; - a longitudinal pushing element along said rotation axis, said nut and said longitudinal pushing element being independent of each other and rotatable about said rotation axis under the action of said drive means; said longitudinal pushing element being fitted into said nut; - coupling means (10, 11, 15, 16) configured to mechanically couple said nut and said longitudinal pushing element with said shaft, such that a rotation of said nut and/or of said longitudinal pushing element determines a translation of said shaft along said rotation axis; said coupling means (10, 11, 15) comprising: - an intermediate coupling stage interposed between the nut and the longitudinal pushing element, said shaft being at least partially fitted into said intermediate coupling stage and into said longitudinal pushing element.