Abstract: The invention relates to an axial flow fan comprising a wheel having a plurality of blades (1) rotatably mounted within and at distance of at least a casing (4), each blade (1) being provided with an acoustic noise reducing means (10) at the vicinity of the casing (4), characterized in that the noise reducing means (10) are provided at the downstream face (I) of the blades (1) and made by a fold of material (10A) forming an outgrowth relatively to the surface of each blade (1) and whose external face (12) forming the outline is approximately tangential to the tip of each blade at its upper part.