Abstract: A coupling device for an agricultural machine including a support for hitching to a tractor and at least one arm articulated to the support and protruding from the support in a direction parallel to a direction of advance of the tractor, the arm carrying, in an articulated manner, a chassis carrying a work element having a cutting angle relative to the ground to allow fine control of the cutting angle during movements of the work element. The coupling device further includes an upper connecting-rod, a lower connecting-rod, and a central connecting-rod, each of the upper and lower connecting-rods is articulated to the support and the central connecting-rod to form, projected in a vertical plane parallel to the direction of advance, a deformable quadrilateral, and the central connecting-rod is articulated to the chassis. An agricultural machine can include the coupling device.