Abstract: An apparatus for supplying an air-fuel mixture through a collecting passage of an intake manifold to a cylinder of an internal combustion engine. The flow of the air-fuel mixture from the intake passageway of a throttle body is discharged transversely into the collecting passageway so that the mixture strikes a region on a side surface of the collecting passageway. Also provided is an arrangement for supplying an auxiliary air stream into the collecting passageway from a location across the striking region from the engine cylinder, which arrangement directs the auxiliary air toward the center of the striking region.