To provide a full-color flat display device which is suitable as a high- definition large screen display for interior use and which is low cost, high luminance and long life.

Green and blue light sources G, B are prepared from organic EL elements using a light emitting layer emitting green light and a light-emitting layer emitting blue light, respectively, on an assembling substrate 1 for an EL device having through holes 1a in the position of a red light source. Red light sources R prepared by molding a red lightemitting LED semiconductor pellet in a transparent resin and mounted on a LED assembling substrate 2 are inserted into the through hole 1a. The height of the light-exiting face of the light source R from the substrate face of the organic EL assembling substrate 1 is made almost equal to the height of the light exiting face of the light sources G, B. The height of each LED semiconductor pellet from the substrate face of the organic EL assembling substrate 1 is determined in such a manner that the viewing angle of each color light of green, blue and red is almost equal to others.