Device that makes it possible to move a conventional single-wheel or single/double-wheel ditcher to the right side, over the tractor’s overall dimensions. The GSI hydraulic side arm is a piece of trailed equipment to be connected to the tractor via three-point hitch. It is fitted with a supporting wheel that prevents overloading the tractor and protects from overturning. During transport, the device translates and closes up, and the ditcher falls back within the tractor’s overall dimensions. It is fitted with an articulated arm that makes it possible to perform the excavation on the side of the tractor even where there are obstacles and significant height differences from the road surface. The self-levelling system constantly maintains the ditcher in the correct position, with no need for operator action. Motion transmission is hydraulic and it is powered by an independent system, fitted with cooling system and driven by PTO shaft connected to the tractor’s PTO. The drives are controlled via an electric-hydraulic joystick.