an exposure apparatus which includes a projection optical system configured to project a pattern of a reticle onto a substrate and exposes the substrate to light via the reticle and the projection optical system with a gap between the projection optical system and the substrate filled with liquid , comprises a liquid immersion system configured to supply the liquid to the gap and to recover the liquid from the gap ; and a generator configured to generate at least one of an electric field and magnetic field in a path of the liquid of the liquid immersion system .