PURPOSE: To easily obtain a wide visual field and to easily and rapidly perform the visual inspection of a fuel rod by arranging a predetermined number of forward visual type fiberscopes each consisting of an optical fiber and an objective lens and integrating them in a sheet form.

CONSTITUTION: This fiberscope is constituted so that a prism 4 integrally and continuously formed in the arranging width of forward visual type fiberscopes 1...1 provided in parallel is provided in front of the fiberscopes 1...1 and the wide visual field S continuing by the connection of the visual fields of the respective forward visual type fiberscopes 1...1 is formed as shown in a drawing by the actions of the prism 4 and objective lenses 3 by controlling the distance (l) between the prism 4 and the objective lenses 3...3 of the forward visual type fiberscopes and, by this constitution, the image reflected by the prism can be continuously obtained.