Respiratory mask comprising a mask body fixed to a nasal cushion, said nasal cushion comprising a hollow body with an internal chamber, and a pair of nasal prongs each connected to and integral with the hollow body, said hollow body further comprising a peripheral border comprising a connecting structure (11, 13; 12, 14) for fixing or coupling the hollow body to the mask body, the connecting structure (11, 13; 12, 14) comprising an outer wall and an inner wall separated from each other by an intermediary spacing, characterized in that: - the outer wall of the nasal cushion comprises a first radial expansion projecting in the intermediary spacing toward the inner wall, and said inner wall comprises a second radial expansion projecting in the internal chamber of the hollow body, - the outer wall and the first radial expansion of the nasal cushion form a hook-like structure, said first radial expansion comprising a first bevelled front face, - the second radial expansion of the nasal cushion forms a boss on the inner surface of the inner wall, - and the mask body comprises:. an abutment structure comprising a second bevelled front face, and cooperating with the first radial expansion of the cushion, when the cushion is set in place into the mask body, and. a lodging having a wall portion cooperating with the boss structure on the inner surface of the inner wall of the second radial expansion of the cushion, when the cushion is set in place into the mask body, thereby firmly maintaining the nasal cushion on the mask body thanks to the combination of actions of the hook-like structure of the outer wall of the cushion that cooperates with the abutment structure of the mask body, and of the projecting boss of the second radial expansion of the cushion that comes into contact, in a non-sliding way, with the surface of the wall portion of the mask body, while the cushion is coupled to the mask body, said boss further acting as a gasket ensuring a gas tightness between the second radial expansion of the cushion and the wall portion of the mask body. - the outer wall of the nasal cushion comprises a first radial expansion projecting in the intermediary spacing toward the inner wall, and said inner wall comprises a second radial expansion projecting in the internal chamber of the hollow body, - the outer wall and the first radial expansion of the nasal cushion form a hook-like structure, said first radial expansion comprising a first bevelled front face, - the second radial expansion of the nasal cushion forms a boss on the inner surface of the inner wall, - and the mask body comprises:. an abutment structure comprising a second bevelled front face, and cooperating with the first radial expansion of the cushion, when the cushion is set in place into the mask body, and. a lodging having a wall portion cooperating with the boss structure on the inner surface of the inner wall of the second radial expansion of the cushion, when the cushion is set in place into the mask body,. an abutment structure comprising a second bevelled front face, and cooperating with the first radial expansion of the cushion, when the cushion is set in place into the mask body, and. a lodging having a wall portion cooperating with the boss structure on the inner surface of the inner wall of the second radial expansion of the cushion, when the cushion is set in place into the mask body,