Hairdrying device consisting of a main body equipped with an external body , an air inlet located at the rear part (P) of the device and a air outlet located at the front part (A) of the device , and wherein said main body also comprises: a duct allowing the air to flow from said inlet to said air outlet , at least one fan adapted to facilitate the flow of air inside said duct , and at least one cap , wherein said cap is constituted by a substantially spherical or hemispherical portion adapted to at least partially surround said fan and by a substantially cylindrical terminal portion facing towards said air inlet , wherein said terminal portion has a smaller diameter than the diameter of said substantially spherical or hemispherical portion of the cap , and the portion of said body located outside of said main body at said terminal portion of said cap is provided with a depression formed in said body , in the shape of a concavity facing outwards and arranged along substantially the entire circular portion of said external body at said end portion of said cap , characterized in that said concavity consists of a) a first portion facing said front part (A) of the device , b) a second portion facing said rear part (B) of the device , and c) a central portion intermediate between said first and second portion wherein there is a slope change of said concavity , wherein the diameter (D1) in said first portion decreases in the direction from said front part (A) of the device towards said central portion , the diameter (D2) in said second portion increases from said central portion towards said rear part (P) of the device so that the diameter (D3) at said central part is smaller than both the diameter (D1) in said first portion and the diameter (D2) in said second portion . at least one cap , wherein said cap is constituted by a substantially spherical or hemispherical portion adapted to at least partially surround said fan and by a substantially cylindrical terminal portion facing towards said air inlet , wherein said terminal portion has a smaller diameter than the diameter of said substantially spherical or hemispherical portion of the cap , and the portion of said body located outside of said main body at said terminal portion of said cap is provided with a depression formed in said body , in the shape of a concavity facing outwards and arranged along substantially the entire circular portion of said external body at said end portion of said cap , characterized in that said concavity consists of a) a first portion facing said front part (A) of the device , b) a second portion facing said rear part (B) of the device , and c) a central portion intermediate between said first and second portion wherein there is a slope change of said concavity , wherein the diameter (D1) in said first portion decreases in the direction from said front part (A) of the device towards said central portion , the diameter (D2) in said second portion increases from said central portion towards said rear part (P) of the device so that the diameter (D3) at said central part is smaller than both the diameter (D1) in said first portion and the diameter (D2) in said second portion . <EOS>