To provide advertisement information for many area residents effectively by making good use of a store where many people gather and to provide an economical advertisement medium.

This system is equipped with a pair of a driving-side moving body 11 and a driven-side moving body 12 which are equipped with cleaning units 14 and arranged on the outdoor and indoor sides of window glass surfaces across the window glass 5 while attracting each other, a moving means which is provided on the driving-side moving body and moves the driving-side moving body along the glass surface, and a display part 7 for advertisement which is provided on the back of at least one of the pair of the moving bodies. Consequently, the display part 7 can display an advertisement irrelevantly to whether or not cleaning operation is in progress.