A laser crystallization apparatus has a light source, a phase shifter which modulates a laser light from the light source, an illumination system which is provided between the light source and the phase shifter, homogenizes a light intensity of the laser light from the light source and illuminates the phase shifter with the homogenized light, a stage which supports a non-single-crystal semiconductor, an image formation optical system having a plurality of optical members which is provided between the semiconductor on the stage and the phase shifter and forms an image of the modulated laser beam at a desired part on the semiconductor, and a temperature adjustment portion which adjusts a temperature of the optical member by heating or cooling the optical members of the image formation optical system.