An air-fuel ratio control device comprising an electric air bleed control valve which controls the amount of air fed into the fuel passage of the carburetor so that an air-fuel ratio becomes equal to the stoichiometric air-fuel ratio. The degree of opening of the air bleed control valve is increased as electric current fed into the air bleed control valve is increased. Fuel vapor is fed into the intake passage from the canister via a purge control valve. When the purge control valve is opened, and the rate of increase in the amount of current fed into the air bleed control valve exceeds a fixed rate, the current fed into the air bleed control valve is instantaneously increased by a fixed amount.