Abstract: In a fuel supply apparatus and method for a spark ignition type of internal combustion engine, a variable throttle is provided in a bypass between the discharge side and the suction side of a volume type fuel pump. The variable throttle is regulated by a pressure adjusting device which makes the ratio of the differential pressure between atmospheric pressure and the negative static pressure in the air intake of the engine and the pressure on the discharge side of the fuel pump equal to n. The value of n is set so that the flow of the fluid in a jet nozzle connected to the discharge side of the fuel pump will be turbulent. The spray from the jet nozzle is blended with the air sucked into the engine and the mixture is supplied to the engine intake manifold through a volume control device.