Abstract: A bend sensor comprising a sensor section in which a polymer electrolyte film is sandwiched between a pair of electrode films, wherein each of the electrode films contains: a block copolymer (Z) having a polymer block (S) composed of a structural unit derived from an aromatic vinyl compound, and containing an ion-conducting group, and an amorphous polymer block (T) composed of a structural unit derived from an unsaturated aliphatic hydrocarbon; and a conducting particle; which block copolymer (Z) forms a lamellar structure, which bend sensor therefore allows generation of enhanced voltage between the electrode films when deformation of the sensor occurs as it follows movement of an object, is provided.