Abstract: An agricultural machine has a main machine, an additional device coupled with the main machine, a hydraulic unit performing control or working functions and including hydraulic valves and hydraulic supply and return conduits, a control current unit for controlling the hydraulic valves and provided with electrical conductors, plug means conductively connecting the hydraulic conduits and the electrical conductors in a region of a separating point between the additional device and the main machine, the plug means including a plug and a plug socket, and a two-part coupling unit formed so that in a region of separating point the plug and the plug socket, the hydraulic supply and return conduits and the electrical control conductors are installed in the coupling unit in positions corresponding to one another, the coupling unit including one coupling half associated with the main machine and another coupling half associated with the additional device.