PROBLEM TO BE SOLVED: To attain not only a novel fiberscope apparatus facilitated in the transmission of illumination light toward an observation part but also an image transmission fiber.SOLUTION: The fiberscope apparatus is constituted so that the illumination light L is transmitted to an input side edge face 110A through an image transmission fiber 11, which transmits the light image inputted to an input side edge face to an output side edge face to output the same, via the inside of the image transmission fiber, to be emitted to thereby illuminate an observation part by the emitted light and the light image formed in the input side edge face is transmitted to an output side edge face 110B by an object optical system 100 to be converted to image data by an imaging element 124. In this fiberscope apparatus, an incident cross section 110C crossing the axis of an optical fiber bundle is formed outside the image transmission region of the optical fiber bundle between the input and output side edge faces of the image transmission fiber 11 and the illumination light from at least one illumination light source 121a is applied into the optical fiber bundle 110 from the incident cross section 110C.
