To provide a method and a device for an external wall washing of a high building to wash the external wall surface of a high building such as a beautiful appearance chimney.

This device comprises a protruding beam mechanism 2, which is set on the roof of a high building, hangs a wire 3 along the external wall surface E, and can regulate the wire location at a location being suitable for a washing work, a rotary brush, a detergent feeding nozzle and a high pressure water jetting nozzle being loaded in a gondola 1A, which is attached to the wire 3, and can be vertically moved along the external wall surface. A slide shoe, which is projected out from the side surface of the gondola 1A, and keeps an interval between the gondola 1A and the external wall surface at a specified location, or changes the interval between the protrusion on the external wall surface and the gondola 1A, is formed. By the provision of the slide shoe, even when there is an obstacle having unevenness such as a bay window on the external wall surface E to be washed, the obstacle can be gotten over, and the work can be continued without trouble.