Abstract: The invention relates to an anti-fall device automatically lockable on a safety rope, wherein the two cheeks of the gutter comprise a blind notch in L form, opening out on the edge of the corresponding cheek, while the ends of the pivot pin of the two elements of the lever project laterally in order to engage in said notches. The free end of that element of the lever which does not bear the cam is mounted to rotate about a pin sliding in a slideway made on an extension of one of the cheeks of the gutter, this pin being elastically loaded in the direction opposite that of the notches. A pivoting lock borne by one of the cheeks of the gutter is maintained elastically in a position in which it closes the bottom of the notch of the corresponding cheek.