A microscope includes a main body, a transmitted light source, and a transmitted-light illumination optical system. The main body has a substantially C-shape when viewed from side, and is composed of a lower horizontal portion, an upper horizontal portion, and a brace portion. The brace portion connects between the lower horizontal portion and the upper horizontal portion on their rear side. The transmitted-light illumination optical system brings an illumination light from the transmitted light source to a specimen supported by the main body, and illuminates the specimen with the illumination light transmitted therethrough. The transmitted-light illumination optical system and the transmitted light source are removably attached to the lower horizontal portion of the main body.