An exposure apparatus for exposing a pattern of a reticle onto a plate using a light from a light source and an optical system includes a measuring part for obtaining polarization information of the light that has passed the optical system, the polarization information including at least one of polarized light intensities, a ratio between the polarized light intensities, a degree of polarization, and a retardation of two orthogonal directions that are both parallel to the optical axis, and a controller for controlling, based on a measurement result by the measuring part, at least one exposure parameter of the light source and the optical system.