PURPOSE: To provide a display device capable of independently exchanging a radiation source between a light housing and an illumination system and keeping optimum homogeneity and lightness even after exchange.

CONSTITUTION: This display device is provided with a support 3, a planar waveguide 7 is provided on the support 3 and the waveguide 7 is irradiated by the radiation source 15 on at least one end face 25. The first part of the light housing 13 is the integrated part of the supporting body 3 and a second part 19 is attachable and detachable so as to exchange the radiation source 15. The light housing 13 houses a reflector 29 for reflecting radiation further. The light housing 13 and the waveguide 7 constitute the illumination system 5 for illuminating a transmission type display panel 11 provided on the waveguide 7. The radiation source 15 is provided with a lamp holder 31 and the radiation source 15 is free to the reflector 29 and is at a position in a distance (d) from the waveguide 7.