PURPOSE: To prevent an output from being limited owing to a protective member in the captioned device including a netted protective member having a smaller measure than a vibrator provided downstream of the vibrator, by more increasing an effective air passage area of said protective member than the maximum effective air passage area in the vicinity of said fuel supply device.

CONSTITUTION: Air is introduced from the outer periphery of a housing part 2a of an injector 1, while fuel is introduced from a fuel nipple 8 and thereafter guided to a fuel pressure regulator 9 through the circumference of the injector 9 serves to make the fuel pressure a prescribed value, and part of the fed fuel is returned to a fuel tank through a return nipple 10. Here, discharged the fuel from a fuel discharge port 1a by operating the injector 1, the fuel strikes a vibrator 3a and thereby atomized, and thereafter allowed to pass through the protective member together with said air, and supplied to an engine 12 via a suction tube 11. Thereupon, an effective air passage area of the protective member 7 is made larger than the maximum effective air passage area in the vicinity of the injector 1.