A rotary coupling for two different fluids. The coupling includes a fixed housing and hollow shaft mounted rotatably but axially immovably in the housing. The shaft is provided with a central through-flow channel for a first fluid and at least one second through-flow channel parallel thereto for a second fluid. In the housing there are provided two separate supply channels for the two fluids and two sliding ring sealing devices between these channels and the hollow shaft, arranged coaxially with an axis of rotation of the hollow shaft, through which sealing devices the fluids can be fed separately to the through-flow channels. The first sliding ring sealing device is arranged centrally between an inner end of the hollow shaft and a housing part with the first supply channel, while the second sliding ring sealing device surrounds the hollow shaft concentrically and includes a sliding ring rotatable with the hollow shaft and has at least one radial through passage, as well as two sliding rings bearing constantly under spring pressure on its two axially facing end faces. The second sliding ring sealing device is axially movable relative to the housing and the hollow shaft. The rotatable sliding ring is fixed to an inner bush coaxially surrounding the hollow shaft, which inner bush is adapted to be coupled and uncoupled from the hollow shaft in response to an axial sliding movement of the inner bush.