An exposure apparatus includes a reticle provided with at least one mark, and operates on a wafer provided with at least one mark. The apparatus further includes a projection optical system for optically conjugately relating the reticle to the wafer, a mark detecting apparatus for detecting the mark of the reticle and detecting the mark of the wafer through the projection optical system, an illuminator for illuminating the wafer with a sensitizing light, and a phase converting element fixed between the wafer and the reticle for varying the direction of polarization of a light coming from the mark provided on the wafer.