Abstract: A window-pane cleaning device for cleaning window-panes of a building is provided in a cleaning unit which is moved along a window of the building. The device includes a squeezee for cleaning a window-pane, an approaching and retraction servo device for moving the squeezee toward and away from the surface of the window-pane, an inclination angle adjusting servo device for adjusting the inclination angle of the squeezee, sensors for detecting the position and pressing force of the squeezee, and a control device responsive to detection outputs of the sensors for controlling the pressing force and inclination angle of the squeezee to predetermined values respectively at starting of cleaning, during continuous cleaning and finishing of cleaning.