A coupling device, particularly for power-operated machines for agricultural use or the like, includes an oscillating frame which is detachably connected to a hitch assembly of an engine and a movable connection means for associating with the oscillating frame the working means of a power-operated machine the oscillating frame and the movable connecting means are configured to maintain, during use, the working plane of the power-operated machine substantially parallel to the ground, independently of the plane of arrangement of the wheels or of the tracks of the engine.