There are disclosed a projection aligner, and an exposure method, capable of largely increasing the effective focus latitude of a fine pattern by using light having a plurality of different wavelengths to perform projection exposure and by setting a plurality of focal planes on an identical optical axis by means of chromatic aberration of the projection lens. The present invention makes it possible to cope with insufficient depth of focus caused by a shortened wavelength of exposure light, an increased numerical aperture of the projection lens, increased uneven topography of the substrate surface incurred from the device structure formed in three dimensions, inclination of the substrate, and field curvature of the projection lens, for example.