This invention relates to an exposure apparatus for synchronously scanning a mask and a photosensitive substrate with respect to a plurality of projection optical systems, thereby properly transferring an entire pattern area on the mask onto the photosensitive substrate. A plurality of sets of mask-side reference marks and substrate-side reference marks are arranged at positions corresponding to each other on the mask surface and the photosensitive substrate surface and at least at two positions conjugate with the plurality of projection optical systems. The displacement amount between an image of a mask-side reference mark or a substrate-side reference mark formed on the corresponding substrate-side reference mark or mask-side reference mark through the projection optical system and the position of the substrate-side reference mark and the mask-side reference mark is measured. The imaging characteristics of the plurality of projection optical systems are corrected in accordance with the displacement amount.
