The method of correcting a residual aberration of a projection optical system, which is used for projecting a pattern of a photo mask onto a photosensitive film located on a substrate, the method includes calculating an effect of a residual aberration on a given pattern on the basis of the residual aberration of the projection optical system obtained by measurement, calculating a moving amount of an adjustable aberration in the projection optical system such that the effect of the residual aberration becomes minimum in a given area, and moving the adjustable aberration in accordance with the calculated moving amount.