An exposure apparatus for efficiently exposing patterns onto corresponding regions of a substrate. The apparatus includes a first wafer stage, a second wafer stage, an alignment sensor which detects marks of wafers on the wafer stages, a projection optical system which irradiates a first region of a wafer with first exposure light, and an imperfect shot region exposure system which irradiates a second region of a wafer that differs from the first region with second exposure light. The imperfect shot region exposure system irradiates the second region of a wafer held on the second wafer stage with the second exposure light.