A sensor includes a stretchable substrate having a stretching property, and a plurality of wires provided to the stretchable substrate, and the plurality of wires includes a first wire, and a second wire larger in resistance value variation due to extension of the stretchable substrate than the first wire. Further, the sensor includes a detection section adapted to correct a resistance value of the second wire in accordance with a resistance value of the first wire, and detect the extension of the stretchable substrate based on the resistance value of the second wire which has been corrected. Further, the detection section detects deterioration of the plurality of wires in accordance with the resistance value of the first wire.