There is provided a light source unit which includes a luminescent light source which receives excitation light so as to emit light of a predetermined wavelength band, excitation light sources which shine excitation light on to the luminescent light source, a reflection space having the luminescent light source in an interior thereof and an emission space which emits luminescent light source light emitted from the reflection space from an emission port whose area is made smaller than the area of the luminescent light source and a projector which employs the light source unit.