An exposing apparatus for a fabricating process of a flat panel display device includes a light source emitting a light; a beam edge cutter for improving an uniformity of the light from the light source; an exposing mask under the beam edge cutter and including a pattern; a gas jetting unit between the beam edge cutter and the exposing mask and jetting a gas through a space between the beam edge cutter and the exposing mask; and a stage, where a substrate for the flat panel display device is disposed, under the exposing mask.