Bending sensor

A bending sensor comprising:

• a flexible segment,
• a pressure-sensitive electrically-conductive resin film formed on the flexible segment, said resin film being made of pressure-sensitive electroconductive ink and coated on the segment, said resin film having a characteristic such that an electric resistance value is reduced as a pressure on the resin film increases and when the segment is bend-deformed 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,
• a pair of electrodes to be attached to the resin film, said electrodes outputting a resistance change of the resin film when the segment is bend-deformed to thereby detect bending of the flexible segment, and
• a flexible base portion having said electrodes thereon, said base plate having an elongated shape to be bent together with the flexible segment and being disposed such that the resin film and the electrodes are sandwiched between the segment and the base plate.