The upper end of a static gas bearing member of a wafer side seal unit is connected to an edge section on the outgoing side of an exposure beam of a chamber in an air tight state via bellows, and the lower end surface is in a state forming a predetermined clearance with a wafer and a wafer holder. By this arrangement, the inside of the chamber is isolated from the outside. Accordingly, it becomes possible to maintain a vacuum environment in the periphery of the optical path of the exposure beam without arranging a vacuum chamber to house a wafer, a wafer holder, and a wafer stage, which allows the size of the entire exposure apparatus to be reduced, and also makes it easy to have access to the vicinity of the wafer stage.