PURPOSE: To expose a photosensitive substrate to such an isolated pattern as a contact hole with excellent resolution and a sufficient depth of focus by projecting the pattern upon the substrate.

CONSTITUTION: After a wafer W is exposed to the pattern image of a first reticle R1 by projecting the pattern image upon the substrate while such a phase plate 15 that the entire area of the plate 15 is divided into 2m pieces (m is a natural number of ≥2) of radial areas around its optical axis AX and each adjacent areas of the radial areas give a phase difference of π against the exposing light is positioned to the pupil surface of a projecting optical system PL, the phase plate 15 is removed from the optical system PL and the wafer W is exposed to the pattern image of a second reticle R2 which is almost the same as the inverted pattern of the first reticle R1 by projecting the pattern image upon the wafer W.