A bright-field light source for a surgical microscope emits visible light whose spectral intensity in a wavelength at the wavelength (672 nm) of fluorescence radiated from an observation object is weaker than that of the remaining wavelength regions of the visible light. With the bright-field light source, the surgical microscope allows a clear observation of the periphery of the fluorescent object. The spectral intensity of the visible light from the bright-field light source is relatively suppressed in the wavelength region of the fluorescence radiated from the observation object. Accordingly, the visible light from the bright-field light source never bothers observation of the fluorescent object. The bright-field light source and an excitation light source such as a semiconductor laser unit are mounted on the surgical microscope without a need of additional supports.
