The invention relates to a chronograph mechanism (7) including an elapsed time indicator member (17), a reset control member (21), a reset device (25) for said indicator member, which includes a hammer (61), mounted in translation between an inactive position, where the hammer (61) is moved away from heart-pieces (55, 57, 59) that are connected to the indicator member (17), and an active position where stop members (54, 56, 58) of said hammer exert a reset force against said heart-pieces.According to the invention, the hammer (61) includes two studs (64, 66) mounted so as to slide in holes (100, 102) such that the movement vectors (L, K) of the studs (64, 66) between said positions are collinear and not aligned.The invention concerns the field of chronographs.