A device for transferring a hydraulic working pressure in a pressure fluid for pressure actuating hydraulic units of deep sea systems, in particular deepwater wells, includes a first pressure chamber (19) for the pressure fluid, a displaceable piston arrangement (9, 11, 13) for changing the volume of the pressure chamber (19), and at least one second pressure chamber (21) in a cylinder arrangement (1). The surrounding pressure of the deep sea can be applied to the second pressure chamber for a displacement of the piston arrangement (9, 11, 13) generating the working pressure in the first pressure chamber (19). A pressure accumulator (37) is associated with the cylinder arrangement (1). The displaceable separating element (41) of the pressure accumulator separates a chamber (45) connected to the seawater from an actuating chamber (43) containing an actuating fluid and connected to the second pressure chamber (21) to apply the deep sea pressure to the second pressure chamber by the actuating fluid.