An exposure apparatus for exposing a pattern of a reticle onto a plate includes a projection optical system for projecting the pattern onto the plate, a switch for switching a polarization of a light for illuminating the reticle from a first polarization state to a second polarization state different from the first polarization state, and an adjuster for adjusting an aberration of the projection optical system when the switch switches the polarization of the light from the first polarization state to the second polarization state.