There is provided a light source unit comprising a first and second light sources, a luminescent light emitting device having a light emitting plate, a light source control device controlling the illumination of the light sources and driving of the light emitting plate, and a light guiding optical system guiding light from the light sources and luminescent light from the light emitting plate so that optical axes coincide to be directed in the same direction, wherein the light emitting plate includes a first area with a luminescent material layer on a reflection layer, a second area transmitting light from the light sources while diffusing it and a third area with a luminescent material layer on a dichroic layer, and wherein the light emitting plate includes a drive motor positioning repeatedly sequentially the first, second and third areas in an optical axis position of light from the light sources.