The acoustic louver is installed in a place having enough area for ventilation where the rectangular sound attenuator is not available, but needs to be soundproofed. The casing is made of a galvanized steel plate with the thickness of 1.0~2.3 mm, and the inside of the louver splitter is filled with sound- absorbing material. It can prevent damage against the air current speed of 30M/S and the size of the acoustic louver splitter should be at least 150 mm.