A plane illumination apparatus has an optical device, an irradiation unit, and a light guide plate. The irradiation unit makes the coherent light beams scan the surface of the optical device, the light guide plate comprises a light take-out portion to take out coherent light beams to outside while making coherent light beams propagate between a first end face on which coherent light beams from the optical device are incident and a second end face provided to face the first end face, the specific zone is provided inside the light take-out portion or along the first end face, or along the second end face, the light take-out surface is a third end face that is connected to the first and second end faces, and the irradiation unit is provided at a rear side of a fourth end face that is an opposite side to the light take-out surface.