To provide a wall-surface mounted illumination signboard device improved in performances, which has a compact signboard system easy to mount and construct, can reduce the power consumption of a light source and extend the life thereof, can be extremely easily subjected to maintenance work such as cleaning with a minimized cost burden for maintenance and management, can easily respond to pattern replacement or damage repairing, can efficiently use the light of the light source to illuminate a signboard, and is excellent in quality stability to strong wind or the like.

The wall-surface mounted signboard device includes one set of upper and lower signboard attachment tools 5 and 6 provided on a wall surface 1; and a signboard unit 2 including a cylindrical molded product having a substantially elliptic sectional shape, the cylindrical molded product including an illumination thin light source module installed to its short diameter-directional rear wall, and suspension members 25b attachable and detachable to the signboard attachment tools on the wall surface 1, which are provided on an upper part and a lower part of the short diameter-directional rear wall of the cylindrical molded body. The front surface side of the cylindrical molded product is translucent, while the rear back side thereof is transparent.