An endoscope light source system includes a light source module, an insertion module and a light guide path. The light source system further includes a light connector which is provided on the light guide path and optically connects an auxiliary light guide path to the light guide path, such that auxiliary light is guided to the light guide path from the auxiliary light guide path which guides the auxiliary light and an irradiation module which emits at least one of light-source light which is guided by the light guide path and the auxiliary light which is guided by the light guide path, to an outside of an endoscope as illumination light, and radiates the illumination light to a to-be-illuminated part.
