A light source unit includes a red light source, a first blue-light source, a fluorescent material, a second blue light source and an optical system. The red light source emits light in red wavelength range. The first blue-light source emits light in a first blue-wavelength range. The fluorescent material receives the light in the first blue-wavelength range and emits light in a green wavelength range. The second blue-light source emits light in a second blue-wavelength range whose wavelengths are longer than those in the first blue-wavelength range. An optical system guides the light emitted from the red light source, the light emitted from the second blue-light source, and the light emitted from the fluorescent material, along a unique optical path.