Atomizing air flowing in an atomizing gas passage is merged with a fuel spray to promote atomization of the fuel, and carrier air flowing in a carrier gas passage is merged with the fuel spray at a further downstream position so as to surround the fuel spray. By doing so, the atomized fuel spray is carried to the downstream side so as to prevent the fuel spray from adhering onto the wall surface. The starting-up performance, fuel consumption and exhaust gas cleaning of an internal combustion engine are improved in this way.