The present invention provides a lithography apparatus which forms a pattern by sequentially irradiating a first region and a second region on a substrate with a beam, the apparatus including a beam detector configured to detect the beam, and a processor configured to obtain position information of the second region by giving a weight to first position information of the second region based on an output from the beam detector before irradiation of the first region with the beam, and giving a weight to second position information of the second region based on an output from the beam detector after the irradiation.