An exposure apparatus for exposing a pattern of a reticle onto a substrate includes a projection optical system for projecting the pattern onto a substrate, the exposure apparatus exposing the substrate through a flammable liquid that is filled in a space between the substrate and a final lens of the projection optical system closest to the substrate, and an explosion-proof unit for shielding an ignition source that can ignite the liquid or vapor of the liquid, from the liquid and the vapor.