Provided is a multiple light source microscope which is capable of performing not only electron image observation but also fluorescence image observation, fluoroscopic image observation and the like for the same biological tissue sample, and is provided with a plurality of observation-use light sources. Disclosed is this multiple light source microscope configured by: an optical microscope unit for observing fluorescence, provided with a light source unit; and a scanning electron microscope unit, wherein the optical microscope has a Cassegrain mirror with an aspherical reflecting surface, and the Cassegrain mirror is arranged in a lens barrel of the scanning microscope unit so as to be coaxial with an optical axis of an electron beam of the scanning electron microscope unit.