The fuel flows from the guide channels into the swirl chamber and is guided to the nozzle hole while swirling in the swirl chamber in the identical direction. The nozzle hole is divided into a portion near a fuel-inflow end and a portion near a fuel-outflow end. The portion near the fuel-outflow end of the nozzle holes has a flow passage cross-sectional area gradually increasing towards a fuel outflow-side opening end, and includes a curved surface formed by smoothly connecting an inner surface of the nozzle holes at an upstream end side in a fuel flow direction to an inner surface of the nozzle holes at the portion near the fuel-inflow end so as to smoothly and gradually increase the flow passage cross-sectional area. The curved surface ensures further thin film-like flow by expanding a flow of the fuel in the nozzle holes by the Coanda effect.