To provide an automatic cleaning device for a sound insulating wall capable of automatically cleaning at a low cost the surface soil of the transparent sound insulating wall erected along a road or a railroad line.

This automatic cleaning device 10 for the sound insulating wall is provided with a pair of bar-like guide parts 11 erected in the positions of partition parts 3 on a foundation wall part 2; a bar-like cleaning member 13 having a support bar part 14 engaged at both end with the pair of guide parts 11 and mounted to be vertically slidable along the guide parts, and a brush part 15 formed of bristles made of plastic fiber, and attached along a support bar to come in contact with a transparent plate 4 of the sound insulating wall 1; and a wind receiving sail part 17 mounted on the opposite side to the brush part of the support bar part 14 of the cleaning member and extended vertically to the transparent plate 4. It is preferable to incline the wind receiving sail part downward on the front side in the proceeding direction of a vehicle to the rear side.