A measuring endoscope apparatus is disclosed having a light source unit that emits low coherence light, a probe that illuminates the observation object with the low coherence light and that collects light reflected by the observation object, and a single optical fiber that optically connects the light source unit and the probe. The light source unit includes a first low coherence light splitting part and an optical path length adjustment part. The probe includes a second low coherence light splitting part, a low coherence light multiplexing part, a lens that forms images using light returned from the observation object and an image detector that captures interference patterns and/or images using light reflected by the observation object. By using the low coherence light, surface conditions, such as roughness, can be accurately measured.