The present invention concerns a coupling device (1) for an agricultural machine (20) comprising a support (2) for hitching to a tractor (3) and at least one arm (4) hinged to the support (2) and projecting from the support (2) in a direction parallel to the direction of forward movement (A) of the tractor (3), said arm (4) hingedly carrying a chassis (6) carrying a working member (8) having a pitch angle relative to the ground. In view of allowing the fine control of the pitch angle during movements of the working member (8), the coupling device (1) comprises an upper link (17), a lower link (18) and a central link (19), each of the upper and lower links (17, 18) is hinged to the support (2) and to the central link (19) to form a deformable quadrilateral projecting on a vertical plane parallel to the direction of forward travel (A), and the central link (19) is hinged to the chassis (6). The invention also relates to an agricultural machine (20) comprising such a coupling device (1).
