A system (1) for resetting a chronograph is provided with a chronograph counting geartrain (2), which includes a minute counter having a minute wheel set (4), and a seconds counter, which includes a chronograph wheel set (3). The system includes a hammer held blocked by a blocking means (11) and displaceable from an inactive position, where the hammer is blocked by the blocking means, and an active position, when the hammer is unblocked, for resetting the chronograph in contact with the various wheel sets (3, 4); a flexible element (10) connected between a reset control means (12) and the hammer for resetting the chronograph, and configured to store energy during a displacement of the control means and before unblocking the hammer blocked by the blocking means to be able, when the hammer is unblocked, to restore this stored energy and drive the hammer to reset the chronograph.