Abstract: A hydraulic turning device for a turn plow comprises a substantially upright double acting cylinder having a piston dividing the cylinder into an upper and a lower compartment and being operatively connected to the turn plow for turning the latter in two steps between a first and a second through 180.degree. reversed position. The upper and lower cylinder compartments are connected by fluid passage with a control device having a fluid inlet passage and a fluid return passage, and which is provided for reversing the movement of the piston in the cylinder wth a valve having an axially movable valve spool, a reversing piston and a reversing valve, in which the valve spool controls filling of the lower cylinder compartment. The control device includes further a pressure valve located between the upper cylinder compartment and the fluid return passage.