The present invention comprises a light modulation optical system having a first element which forms a desired light intensity gradient distribution to an incident light beam and a second element which forms a desired light intensity minimum distribution with an inverse peak shape to the same, and an image formation optical system which is provided between the light modulation optical system and a substrate having a polycrystal semiconductor film or an amorphous semiconductor film, wherein the incident light beam to which the light intensity gradient distribution and the light intensity minimum distribution are formed is applied to the polycrystal semiconductor film or the amorphous semiconductor film through the image formation optical system, thereby crystallizing a non-crystal semiconductor film. The pattern of the first element is opposed to the pattern of the second element.