An underwater cleaning robot comprising a robot body (2) moving along the surface of a cleaning object existing in the water, and a cleaning nozzle unit (3) provided in the robot body and cleaning the cleaning object by jetting high pressure water toward the surface of the cleaning object wherein an auxiliary cleaning work machine (70) is attached to the robot body. The auxiliary cleaning work machine comprises a rotating shaft (76) provided rotatably in the work machine body (71), a cleaning nozzle unit (72) provided at a lower part of the rotating shaft and cleaning the cleaning object by jetting high pressure water and rotating integrally with the rotating shaft by the reaction of high pressure water jetted toward the surface of the cleaning object, and a propeller (73) provided at an upper part of the rotating shaft and generating a force for pressing the work machine body toward the surface of the cleaning object by rotating as the rotating shaft rotates.
