Abstract: An extendable and retractable cleaning apparatus includes a multi-stage extendable and retractable arm assembly formed of a plurality of cylindrical members assembled in a telescopic manner, an ejection nozzle provided at a tip end of the innermost cylindrical member of the arm assembly, a mount housing surrounding a substantially central portion of the arm assembly to rotatably support the arm assembly and a casing integrally formed at a base end of the outermost cylindrical member of the arm assembly to form a pressure chamber in cooperation with the assembly. A rotational driving device is provided within the housing for rotationally driving the arm assembly. A washing liquid feed hose is connected to the ejection nozzle. A compressed air feed pipe has one end mounted to the casing to communicate with the pressure chamber.