The modular device of the sternum prosthesis comprising a plate (1) and an attachment means (2) to the ribs, where each of the attachment means (2) to the ribs comprises an end (20) for fixing to the plate (1) and one end (21) provided with a means (22) of attachment to one side. The plate (1) comprises at least one slide (10) arranged longitudinally, intended to receive the ends (20) for fixing the attachment means (2), each through a sliding element (3) is configured to be displaceable in the slide (10) and to allow the pivoting of the means of attachment (2) which is secured, the sliding means (3) being associated with locking means (33, 25) adapted to immobilize it in translation in the slide (10) to the desired location and to prevent the pivoting of the means of attachment (2).
