Abstract: A bending sensor of the invention is formed of a flexible segment, a pressure-sensitive electrically-conductive resin film formed on the flexible segment, and a pair of electrodes to be attached to the resin film. The resin film is made of pressure-sensitive electroconductive ink and coated on the segment. The resin film has a characteristic such that an electric resistance value is reduced as a pressure on the resin film increases. When the segment is bend-formed at an inflection point by receiving an outer force, the segment provides a pressure to the resin film at the inflection point to produce an inner stress in the resin film. When the segment is bent-deformed, the electrodes output a resistance change of the resin film to thereby detect bending of the flexible segment.