A light irradiation apparatus for irradiating an object with light, includes a plurality of line-shaped light blockers arranged at a predetermined center-to-center interval, and configured to at least partially block light, and a plurality of line-shaped light irradiators arranged to overlap some of the plurality of light blockers so as to irradiate the object with light. The plurality of light irradiators are arranged to form a period not less than twice as large as the center-to-center interval of the plurality of light blockers.