An exposure apparatus for exposing a substrate to exposure light via a pattern of a mask. The apparatus includes a stage configured to hold one of the substrate and the mask, and to move, a projection optical system configured to project the pattern onto the substrate, a defining member facing the stage and configured to define a space, between the stage and the projection optical system, through which the exposure light passes and which is to be filled with fluid, a first stream mechanism having a first supply port in the defining member and configured to stream the fluid through the space from the first supply port, an exhaust mechanism having an exhaust port in the defining member and configured to exhaust fluid in the space from the exhaust port, and a second stream mechanism having a second supply port different from the first supply port. The second supply port is arranged to surround the space at a lower portion of the defining member, and configured to stream fluid from the second supply port against the stage to seal the space.