The invention relates to a respiratory assistance device comprising: a turbine (30) including a motor (1) that engages with an impeller (25) in order to generate a gas flow； and soundproofing means arranged around at least part of the turbine (30). The soundproofing means comprise a three-dimensional structure (20) arranged around at least part of the motor (1), comprising: at least one central element (20a) defining a central housing (20g) forming a sleeve around at least part of the motor (1) and being spaced apart from the motor (1)； multiple spacer elements (20b), each comprising at least one wall projecting radially outwards, said spacer elements (20b) being arranged along the periphery of the tubular element (20a)； and at least one maintaining element (20c) resting on the motor (1) such as to maintain the three-dimensional structure (20) in position around the motor (1).
