This invention serves to solve the problem of the large irradiation angle upon an observation target of an inclined illuminator type medical binocular microscope, and the problem of structural complexity and light attenuation of a coaxial illuminator type microscope. The microscope A includes the illumination system 2 comprised of the illumination unit 6 with the condensing lens 6d attached at a front tip of the illumination unit, disposes the illumination system retaining member 7 in close proximity to the two observation optical systems structured at the body tube 3, defines the plane 8 including the prescribed lenses of the objective lenses of the left and right observation optical systems 1 (secondary objective lens 1b) arranged closest to the observation target, and arranges the optical axis 2a of the illumination system 2 inside the circle 9 having a diameter connecting the optical axis 1a of the two observation optical systems with respect to the plane 8. The optical axis 2a intersects with the optical axis 1a of the observation optical system 1 at the observation target surface 4a.