Abstract: An apparatus for cleaning surfaces by means of a jet of cleaning liquid comprises a sluicing pipe with a housing provided with a tiltably arranged nozzle assembly. The latter is adapted to perform oscillations by means of a hydraulic motor mounted in the housing and driven by the cleaning liquid flowing to the nozzle assembly. The nozzle assembly is located within the housing and comprises at its front end a contact surface, by means of which it is capable of tilting on the bearing surface provided with a discharge opening on a discharge member located at the outlet of the housing. The discharge member comprises a central flow channel for the cleaning liquid, and the discharge opening has a sectional area greater than the hole area of the nozzle assembly. As a result the reliability is increased, as the apparatus is self-adjusting with regard to the wear caused by the movement of the nozzle assembly. The apparatus is furthermore easily assembled.