An exposure apparatus for exposing a photosensitive medium, the exposure apparatus comprising: an illumination device, said illumination device comprising: an optical device configured to diffuse coherent light beams from respective points to an entire region of at least a specific zone; and an irradiation unit configured to irradiate the coherent light beams to the optical device; a spatial light modulator that is provided at a location overlapped with the specific zone and illuminated by the illumination device; and a light diffusion device provided between the optical device and the spatial light modulator, configured to diffuse coherent light beams from the optical device, the coherent light beams diffused by the light diffusion device being incident on the spatial light modulator while varying an incident angle of the coherent light beams on the optical device with time, wherein coherent light beams modulated by the spatial light modulator are guidable to a surface of the photosensitive medium, characterized in that the irradiation unit is configured to make the coherent light beams scan a surface of the optical device by changing propagation directions of the coherent light beams so that an incident direction of the coherent light beams incident on respective points of the spatial light modulator varies with time, and the optical device is a reflection-type hologram recording medium configured to reproduce an image of a scattering plate, wherein the spatial light modulator is provided so that it is overlapped with the image. an illumination device, said illumination device comprising: an optical device configured to diffuse coherent light beams from respective points to an entire region of at least a specific zone; and an irradiation unit configured to irradiate the coherent light beams to the optical device; an optical device configured to diffuse coherent light beams from respective points to an entire region of at least a specific zone; and an irradiation unit configured to irradiate the coherent light beams to the optical device; a spatial light modulator that is provided at a location overlapped with the specific zone and illuminated by the illumination device; and a light diffusion device provided between the optical device and the spatial light modulator, configured to diffuse coherent light beams from the optical device, the coherent light beams diffused by the light diffusion device being incident on the spatial light modulator while varying an incident angle of the coherent light beams on the optical device with time, wherein coherent light beams modulated by the spatial light modulator are guidable to a surface of the photosensitive medium, characterized in that the irradiation unit is configured to make the coherent light beams scan a surface of the optical device by changing propagation directions of the coherent light beams so that an incident direction of the coherent light beams incident on respective points of the spatial light modulator varies with time, and the optical device is a reflection-type hologram recording medium configured to reproduce an image of a scattering plate, wherein the spatial light modulator is provided so that it is overlapped with the image.