A bore hole scanner includes light projecting means (11 - 13, 5) for projecting a light beam toward a bore hole wall surface, a conical mirror (4) arranged coaxially with respect to a sonde (14) for condensing light reflected from the bore hole wall surface, image forming means (3) arranged in front of the conical mirror (4), photoelectric transducing means (2-1) for converting a light signal into an electric signal, optical fibers (2-2) for introducing an image, which is formed on concentric circles by the image forming means (3), to the photoelectric transducing means (2-1), data processing means for scanning and extracting signals from the photoelectric transducing means (2-1), and for generating and processing image data indicative of the bore hole wall surface, and sonde position detecting means (8 - 10) for detecting the orientation and position of the sonde. Rotating portions are dispensed with by using the conical mirror and optical fibers, and a linear CCD array can be used as the photoelectric transducing means.