A zero-rest device for a timepiece (such as a chronometer), including a first control mechanism (1), a second control mechanism (2), two zero-reset cams (3.1, 3.2, 3.3), and two corresponding zero-reset hammers (4.1, 4.2, 4.3) configured to cooperate with the cams. The device also includes two hammer springs (5.1, 5.2, 5.3) exerting a pre-stress force causing a hammer to pivot in the direction of its corresponding cam, a winding and release mechanism (6) and a locking mechanism (7). The winding and release mechanism is configured to wind the hammer springs during a first phase of an actuation of the first control mechanism and to cooperate, during a second phase of this actuation, with the locking means, such that the locking means passes from a rest position in which the locking mechanism holds the hammers (4.1, 4.2, 4.3) to a release position in which the locking mechanism (7) releases the hammers, which come, in each case under the action of the corresponding hammer spring, into the positions thereof of cooperation with the corresponding cam.