An illumination optical system projects an illumination light onto an observation object via an objective lens. A first observation optical system guides the illumination light reflected by the observation object to a first ocular lens. A second observation optical system includes a second ocular lens for observing the reflected light of the illumination light. An optical system drive mechanism rotates the second observation optical system and arranges the second observation optical system between a first position and second position facing each other. A reflecting member is disposed at a position retracted from the illumination light path and the reflected light path and reflects the reflected light in a direction different from the optical axis. A drive mechanism rotates the reflecting member around a rotation axis orthogonal to the optical axis and guides the reflected light to the second observation optical system arranged at the first or second position.