To provide an aligner enabling a precise overlay of patterns in a predetermined positional relation, and an accurate exposure by precisely correcting in performance of a scan exposure, while characteristics of a pattern image are being corrected.

In the aligner, a pattern of a mask M is projected on a photosensitive substrate P through a projection optical system PL1-PL5, while synchronously moving the mask M and the photosensitive substrate P. The aligner includes a correction mechanism for correcting a pattern image projected on the substrate P, driving equipment for driving the correction mechanism, and a controller CONT for setting at least either one of a driving speed and amount of driving in the driving equipment in accordance with the speed of a synchronous-movement.