Striking mechanism unit (2) for a repeater striking mechanism (100), including a drive plate (3) with a pipe (4) pivoting about an axis (D) and carrying a hook (6) provided with a beak (6A), a detent ratchet (9) pivoting about said axis (D) carrying a pin (8) which is in abutment, through a hole (3A) in said plate (3), on said hook (6) against a spring (7) for the operation thereof when said detent ratchet (9) is pivoting, and depending on the position thereof, said beak (6A) allows or prevents the pivoting of a pipe ratchet (11) of a downstream stage (1) which pivots integrally with a first hour ratchet (13).Said downstream stage (1) includes a second hour ratchet (15) which pivots about said axis (D) and whose toothing is inclined in the same direction as that of said first hour ratchet (13).