Three light sources are provided as a light source. A first light source emits a light in red, a second light source emits a light in green, and a third light source emits a light in blue. Each light source is a light source in which a plurality of LEDs (light-emitting diodes) are arranged in the same plane surface. The first light source, the second light source, and the third light source are arranged on the same plane surface. Furthermore, lines connecting the first light source, the second light source, and the third light source form a triangle. Light fluxes (primary optical axes) of each light source are parallel with each other. The first light source, the second light source, and the third light source are arranged on one piece of a cooling plate.