Abstract: A folding clasp for a wrist-watch, having at least one folding arm (1, 2) articulated with respect to a base plate (3) and a locking device (4) located on the base plate (3). The locking device (4) includes a mobile part (4.5) permitting a locking with an inclined end face (1.1, 2.1) of the at least one folding arm (1, 2) folded down on displacing the mobile part (4.5) in plane (TT') substantially perpendicular to the opening/closing plane (00') of the at least one folding arm (1, 2).