PURPOSE: To reduce the lamination errors between projected images by a method wherein the error amounts due to the distortion of a pattern formation lens and a TTL alignment lens are stored to correct the results in alignment conforming to the stored error amounts and then a pattern is projected on a wafer.

CONSTITUTION: The error amounts between an alignment mark on an ideal lattice image 3a and another alignment mark on a projection image 3b are measured at respective points in an image field to make up a map and further to be stored into a memory 10 and then both images 3a, 3b are aligned with each other using motors 1m, 1n. Resultantly, the lamination errors of Δ×1+Δ×2 are made. At this time, a correction amount processor 1p reads the error amounts corresponding to the positions of alignment marks 4b, 4d out of the memory 10 to convert the error amounts into the correction amounts which are transmitted to the motors 1m, 1n to project a pattern on a reticle 19 on a wafer 1c. Through these procedures, the projection errors due to the distortion of respective lenses can be reduced.