There is provided a light source unit comprising an excitation light shining device for emitting excitation light, a luminescent plate having a luminescent light emitting area on a base material and adapted to emit a luminescent light of a predetermined wavelength band by excitation light from the excitation shining device, two types of light source devices for emitting light of wavelength bands different from that of the light from the luminescent plate, a light guiding optical system for guiding the light from the luminescent plate and the rays from the light sources to a predetermined plane, and a light source control device for controlling the emission from the excitation light shining device and the light sources, wherein a synthetic light or a single-color light are emitted by controlling the emissions from the excitation light shining device and the light sources by the light source control device.