A stereomicroscope includes: an observation optical unit (10) having a zoom optical system (501) capable of modifying zoom degree and an objective lens (6) optically connected to the zoom optical system (501) and receiving an observation light emitted from a sample (2); an illumination unit (7) for emitting an illumination light for illuminating the sample (2); a near coaxial incident light illumination optical system having a reflection mirror (13) inserted into the observation optical unit (10) and out of the optical path of the zoom optical system (501) and applying an illumination light to the sample (2) via the reflection mirror and the objective lens (6).
