A crystallization apparatus according to the present invention includes a first irradiation system which irradiates a predetermined area on a glass substrate having an irradiation target, i.e., an a-Si thin film with light beams having a substantially homogeneous light intensity distribution, and a second irradiation system which irradiates the predetermined area with light beams having a light intensity distribution with an inverse peak pattern that a light intensity is increased toward the periphery from an area in which the light intensity is minimum.