In a lighting unit, fluorescent lights and LEDs having different spectroscopic characteristics are alternately arranged in a direction X on an irradiation plane. The fluorescent lights are arranged in certain intervals so as to provide uniform light intensity even around the end portions of the direction X. The LEDs installed at the ends of the direction X have a light intensity that is weaker than that of other LEDs in order to provide uniform light intensity around the end portions. As a result, the lighting unit provides uniform light intensity across the entire irradiation surface.