An air distributor intended to be fixed on a cylinder head of a thermal combustion engine, said air distributor comprising an inlet orifice opening into an internal volume of said air distributor and a plurality of outlet conduits each intended to connect said internal volume to a respective cylinder of the engine, in which the air distributor comprises: - a main body defining the inlet orifice, and at least partially the internal volume and the plurality of outlet conduits, - an internal cover at least partially defining the plurality of outlet conduits, said internal cover being fixed to the main body by means of mechanical fastening means, and - a perforated structure in one piece disposed between the main body and the internal cover, said perforated structure being configured to, on the one hand, ensure gas tightness between the air distributor and the engine cylinder head, as well as between the outlet conduits, and, on the other hand, participate in the mechanical retention of the internal cover with the main body, and in which - the main body and the internal cover are configured to form at least one groove opening onto an external face of the air distributor which is intended to come to the contact of the engine cylinder head, said groove being able to house at least partially said perforated structure, - the groove comprises a plurality of main segments of annular shape, each of the main segments surrounding one of the outlet conduits, said main segments being connected by a plurality of intermediate segments (155-157; 155'-157/) with a rectilinear profile, characterized in that each main segment of the groove comprises at least one first end segment (151a, 152a, 152a', 153a, 153a', 154a) having substantially a partially annular shape and at least one second end segment (151b, 152b, 152b', 153b, 153b', 154b) also having a partially annular shape, said second end segment end (151b, 152b, 152b', 153b, 153b', 154b) being contiguous to said first end segment (151a, 152a, 152a', 153a, 153a', 154a), and the first end segment (151a, 152a, 152a', 153a, 153a', 154a) is defined only by the main body and the second end segment (151b, 152b, 152b', 153b, 153b', 154b) is defined only by the internal cover. - a main body defining the inlet orifice, and at least partially the internal volume and the plurality of outlet conduits, - an internal cover at least partially defining the plurality of outlet conduits, said internal cover being fixed to the main body by means of mechanical fastening means, and - a perforated structure in one piece disposed between the main body and the internal cover, said perforated structure being configured to, on the one hand, ensure gas tightness between the air distributor and the engine cylinder head, as well as between the outlet conduits, and, on the other hand, participate in the mechanical retention of the internal cover with the main body, and in which - the main body and the internal cover are configured to form at least one groove opening onto an external face of the air distributor which is intended to come to the contact of the engine cylinder head, said groove being able to house at least partially said perforated structure, - the groove comprises a plurality of main segments of annular shape, each of the main segments surrounding one of the outlet conduits, said main segments being connected by a plurality of intermediate segments (155-157; 155'-157/) with a rectilinear profile,