The present invention provides an exposure apparatus including a projection optical system configured to project light from a reticle onto a substrate, a processor configured to estimate a variation in imaging characteristic of the projection optical system, based on a model determined in advance, and an adjusting device configured to adjust the imaging characteristic of the projection optical system based on the variation estimated by the processor, wherein the processor is configured, if an error of the imaging characteristic of the projection optical system adjusted by the adjusting device based on the variation which is estimated based on a first number of models, for estimating the variation, determined in advance without the reticle, does not fall within a tolerance, to generate a second number of models for estimating the variation, the second number being larger than the first number.