Braking device for elevator apparatus, for emergency braking of a cabin that can be moved longitudinally by vertical guides, comprising: - a wedging block attachable to a chassis of the cabin, comprising in turn: - a central slot to house the guide, - a catching element, movable perpendicular to the central slot, and - a braking element movable with respect to the central slot, and attachable to the guide and to the catching element to immobilize the cabin, - an activation electromagnet, and - an articulated actuating mechanism comprising a first sector linked to the electromagnet and a second sector linked to the braking element, wherein the actuating mechanism comprises a friction element, located in the second sector and capable of engaging the guide for fixing a safe position of the cabin on the guide, such that when the actuating mechanism engages the friction element with the guide, and a relative movement of the guide with respect to the cabin occurs, said actuating mechanism moves the braking element in the same direction until it engages the guide, characterised in that the actuating mechanism further comprises: - a first arm, integrally linked to the electromagnet, - a second arm, pivotally linked to the first arm through a first joint, and - a third arm, pivotally linked by a first end to the second arm through a second joint, and linked to the braking element, which it moves, and wherein the friction element is integrally linked to a second end of the third arm; the friction element is a machining located at the second end of the third arm. - a wedging block attachable to a chassis of the cabin, comprising in turn: - a central slot to house the guide, - a catching element, movable perpendicular to the central slot, and - a braking element movable with respect to the central slot, and attachable to the guide and to the catching element to immobilize the cabin, - a central slot to house the guide, - a catching element, movable perpendicular to the central slot, and - a braking element movable with respect to the central slot, and attachable to the guide and to the catching element to immobilize the cabin, - an activation electromagnet, and - an articulated actuating mechanism comprising a first sector linked to the electromagnet and a second sector linked to the braking element, wherein the actuating mechanism comprises a friction element, located in the second sector and capable of engaging the guide for fixing a safe position of the cabin on the guide, such that when the actuating mechanism engages the friction element with the guide, and a relative movement of the guide with respect to the cabin occurs, said actuating mechanism moves the braking element in the same direction until it engages the guide, characterised in that the actuating mechanism further comprises: - a first arm, integrally linked to the electromagnet, - a second arm, pivotally linked to the first arm through a first joint, and - a third arm, pivotally linked by a first end to the second arm through a second joint, and linked to the braking element, which it moves, and wherein the friction element is integrally linked to a second end of the third arm; - a first arm, integrally linked to the electromagnet, - a second arm, pivotally linked to the first arm through a first joint, and - a third arm, pivotally linked by a first end to the second arm through a second joint, and linked to the braking element, which it moves, and