In a slit lamp microscope, ease of maintenance of an illumination-power-supply cable is improved while preventing the cable from appearing untidy. An illumination support arm of a slit lamp microscope is provided with a groove-shaped cable holder in which the illumination-power-supply cable is disposed along the outer surface of the illumination support arm in an externally exposed state. This configuration facilitates replacement of the illumination-power-supply cable even when a problem, such as breaking of the illumination-power-supply cable, occurs, thus improving ease of maintenance. Furthermore, because the illumination-power-supply cable is disposed along the groove-shaped cable holder, the slit lamp microscope has a neat appearance.