A variable venturi-type carburetor comprising a metering jet and at least one air-bleed bore formed on the cylindrical inner wall of the metering jet. The amount of air fed into the fuel passage of the carburetor from the air-bleed bore is controlled by an output signal from the oxygen concentration detector arranged in the exhaust manifold so that the air-fuel ratio of the mixture fed into the cylinder of the engine becomes equal to the stoichiometric air-fuel ratio. The metering needle is arranged so that it contacts the cylindrical inner wall of the metering jet and partially covers the air-bleed bore.
