A light source unit includes a light emitting plate which has a plurality of segment areas and in which a luminescent material layer which emits light having a predetermined wavelength band by receiving excitation light and a transmissive portion which transmits light are formed on at least the plurality of segment areas, a primary light source for emitting excitation light on to the luminescent material, a secondary light source for emitting light having a wavelength band which differs from those of luminescent light emitted from the luminescent material layer and excitation light emitted from the primary light source, a light guiding optical system for guiding light emitted from the light emitting plate and light emitted from the secondary light source to the same optical path, and a light source control means for controlling the emission of light from the primary light source and the secondary light source.