Safety brake for elevator, the elevator having a movable car through a vertical guide, wherein the safety brake comprises: - a wedging block attachable to the elevator car; - a shoe attached to the wedging block; - a braking element with two positions, an initial rest position and an active position, wherein said braking element is located between the wedging block and the vertical guide, such that when an emergency situation occurs, said braking element simultaneously contacts the wedging block and the vertical guide in their active position, causing a safety braking of the elevator; - an activation element electrically powered for activating and deactivating the safety brake; - a first element located in a lower position with respect to the braking element, said first element being vertically movable with respect to the wedging block, wherein the first element has two positions, a first rest position and a second active position, wherein in the event of a power failure of the activation element there is a vertical movement of the first element to its second active position, pushing and moving in turn the braking element from its initial rest position to its active position in which the actuation of said braking element is autonomous, that is, from this point on it is no longer necessary to continue pushing the braking element through the first element; characterized in that the safety brake additionally comprises: - a second element having at least two folded sections, a vertical lateral surface and a horizontal lower surface, wherein a frontal upper surface of the second element is located in a higher position with respect to the braking element, wherein the second element has two positions, a first rest position and a second active position, wherein said second element is movable vertically with respect to the wedging block, such that in the second active position of the second element and the first element being in its second active position, the activation element contacts simultaneously the first element and the horizontal lower surface of the second element, the vertical guide being trapped between the braking element and the shoe, generating a maximum braking force for the elevator. - a wedging block attachable to the elevator car; - a shoe attached to the wedging block; - a braking element with two positions, an initial rest position and an active position, wherein said braking element is located between the wedging block and the vertical guide, such that when an emergency situation occurs, said braking element simultaneously contacts the wedging block and the vertical guide in their active position, causing a safety braking of the elevator; - an activation element electrically powered for activating and deactivating the safety brake; - a first element located in a lower position with respect to the braking element, said first element being vertically movable with respect to the wedging block, wherein the first element has two positions, a first rest position and a second active position, wherein in the event of a power failure of the activation element there is a vertical movement of the first element to its second active position, pushing and moving in turn the braking element from its initial rest position to its active position in which the actuation of said braking element is autonomous, that is, from this point on it is no longer necessary to continue pushing the braking element through the first element; - a second element having at least two folded sections, a vertical lateral surface and a horizontal lower surface, wherein a frontal upper surface of the second element is located in a higher position with respect to the braking element, wherein the second element has two positions, a first rest position and a second active position, wherein said second element is movable vertically with respect to the wedging block, such that in the second active position of the second element and the first element being in its second active position, the activation element contacts simultaneously the first element and the horizontal lower surface of the second element, the vertical guide being trapped between the braking element and the shoe, generating a maximum braking force for the elevator.