A microscope unit comprises: a main lens barrel of an imaging optical system, the main lens barrel being configured capable of being fitted with an imaging sensor and an objective lens; and an illumination lens barrel of an illumination optical system, the illumination lens barrel being connected to the main lens barrel and configured capable of being fitted with a light source, the illumination lens barrel having: a first lens barrel configured capable of being fitted with the light source; and an intermediate lens barrel connecting the main lens barrel and the first lens barrel, and a field stop of light irradiated from the light source being disposed more inwardly than an outer peripheral surface of the intermediate lens barrel is.