PURPOSE: To reduce suction noise by a method wherein the internal space of a sound absorbing chamber, provided near a suction path, is divided into two parts by an elastic film and respective chambers are communicated with the suction path through throttle valves.

CONSTITUTION: The sound absorbing chamber 5 is provided near the suction path 1, connecting a cylinder 2 to a carburettor 3, and the internal space thereof is divided into two chambers by the elastic film 6 while respective chambers 7, 10 are communicated with the suction path 1 through the throttle valves 9, 12. According to this method, standing wave in the suction path is attenuated by resonance type sound deadening function as well as interference type sound deadening function due to vibrations of the throttle valves 9, 12 and the elastic film 6, therefore, the noise of suction may be reduced.