An exposure apparatus for illuminating an original with light from a light
source and for projecting a pattern of the original, as illuminated, onto
a surface to be exposed, includes a hologram, an optical system for
projecting light from the light source onto the hologram, a slit device
disposed at a predetermined position where light of a slit-like shape is
to be substantially produced by the hologram, and an imaging optical
system for illuminating the original with the light passed through a slit
of the slit device. The slit device serves to determine an illumination
region of light projected onto the original.
