Abstract: A multi layered sound-proofing structure comprises: a first layer comprising a light aggregate and a binder and having a bulk density of from 0.1 to 2.0 g/cm.sup.3 and void fraction as continuous void of from 15 to 60%; a second layer of a material having a quality to insulate relatively high frequency sounds and penetrate relatively low frequency sounds; a third layer comprising a light aggregate and a binder, the same as or different from those of the first layer and having a bulk density of from 0.1 to 2.0 g/cm.sup.3 and void fraction as continuous void of from 15 to 60%, the first and second layers each overlying the third layer; and a fourth layer of a material having a high sound-insulating ability and covering all surfaces of a layered structure of said first, second and third layers except for the sound incident surface of said first layer. A perforated plate may be provided over the sound incident surface of the first layer with an air space therebetween.