To enable a plurality of separated places to be uniformly illuminated, by improving incorporation performance into an installation part, in a structure of using an electroluminescence material as a light source.

A light source arranging structure is incorporated into an interior trim device 1 of a cabin, and performs illumination by using electroluminescence material being a light source, and the electroluminescence material is formed in a solid-shaped illumination mold 4 arranged over a plurality of places including an inside part and an outside part of the interior trim device 1, and a light emitting area is limited by being partially covered with a shielding cover 6 installed in the interior trim device 1.