The present invention relates to a stereomicroscope comprising an object observation unit and an electronic image unit. The object observation unit includes an objective lens barrel section and a binocular lens barrel section, with the binocular lens barrel section including an interpupillary adjusting mechanism in a light path following a first image plane. The electronic image unit includes an electronic image display device and a projection optical system The object observation unit has an object observation image that remains fixed in position at the first image plane during interpupillary adjustment of the binocular lens barrel section. The projected image from the electronic image display device is made to be substantially in focus at the first image plane. Images at the first image plane may be relayed to a second image plane. An object observation image formed by the object observation unit and an electronic image formed by the electronic image unit may be observed simultaneously in the same field of view by an observer looking into an eyepiece of a binocular lens barrel section. In one embodiment of the invention, the position within the first image plane of the projected image from the electronic image display device is adjustable within a range such that the projected image may lie within or outside of the field of view of a viewer looking into an eyepiece of a binocular lens barrel section.