The invention concerns an air inlet device for an internal combustion engine. The inlet device in question is provided with an at least partially variable through-aperture by which the inlet behavior is matched to the operating condition of the engine. To achieve an optimal reduction in noise emission depending on the operating conditions of the engine, the inlet device (1) includes at least one inner tube (3) and one outer tube (4). The inlet air stream is drawn irrespective of prevailing operating conditions through the inner tube (3) and a further air stream is drawn through an additional through-aperture whose size can be varied, between the inner tube (3) and outer tube (4). The additional through-aperture is provided with a resilient sealing lip (7, 13).