Described is an agricultural machine comprising: -a frame (2) movable over land (200); - means (4) for working the land, mounted on the frame (2) of the machine in a corresponding work area (31) and positioned in such a way that it faces the land (200); - a first comb unit (5) equipped with teeth (12), mounted on the frame (2) and facing the means (4) for working the land for delimiting at least in part the work area (31) and stopping fragments of land coming from the moving working means (4). The agricultural machine comprises cleaning means (14) mounted on the frame (2) and operatively associated with the comb unit (5) for mechanically removing fragments of land (200) and/or detritus from the teeth (12) of the above-mentioned comb unit (5).