Abstract: Exhaust gas recirculation means by which recirculated exhaust gas is supplied into a portion of a carburetor that is downstream of the venturi section of the carburetor, whereby fouling of easily blocked elements in the upstream portion of the carburetor is avoided, and in which supply of exhaust gas into the carburetor is in opposition to a supplementary supply of air from the atmosphere or from a portion of the carburetor which is upstream of the venturi, air and exhaust gas being supplied through a common port into the carburetor. The pressure of exhaust gas being comparatively high, the supplementary supply of air is steadily decreased as the amount of recirculated gas is increased, whereby the air-fuel ratio of a mixture supplied to an engine is decreased and the mixture is enriched in a manner required when exhaust gas is recirculated.