A manufacturing device for an unvulcanized band-shaped rubber member (R) configured to elongate a band-shaped rubber member (R) to a target length, comprising: a placement portion onto which an unvulcanized band-shaped rubber member (R) cut at a predetermined length is placed in a flat state; a position sensor that detects, across a width direction (W) of the band-shaped rubber member (R), a leading end (Ra) and a trailing end (Rb) of the band-shaped rubber member (R) placed in a flat state; a control unit into which detection data from the position sensor is input; a leading end holding mechanism that holds the leading end (Ra); and a trailing end holding mechanism that holds the trailing (Rb) end, at least the trailing end holding mechanism of the the leading end holding mechanism and the trailing end holding mechanism comprising a plurality of holding portions arranged side by side in the width direction (W) of the band-shaped rubber member (R), and movement portions that each move each of the plurality of holding portions individually in a front-rear direction of the band-shaped rubber member (R), each of the plurality of holding portions is a suchtion pad to suction a top surface of the band-shaped rubber member (R) and a needle-like body that peenetrates into a position midway in the thickness direction of the band shaped rubber member (R), a displacement of each of the movement portions in the front-rear direction being controlled by the control unit based on the detection data and the target length to adjust a degree of elongation in the front-rear direction at or near a held portion of the band-shaped rubber member (R) held by each of the plurality of holding portions . a placement portion onto which an unvulcanized band-shaped rubber member (R) cut at a predetermined length is placed in a flat state; a position sensor that detects, across a width direction (W) of the band-shaped rubber member (R), a leading end (Ra) and a trailing end (Rb) of the band-shaped rubber member (R) placed in a flat state; a control unit into which detection data from the position sensor is input; a leading end holding mechanism that holds the leading end (Ra); and a trailing end holding mechanism that holds the trailing (Rb) end, at least the trailing end holding mechanism of the the leading end holding mechanism and the trailing end holding mechanism comprising a plurality of holding portions arranged side by side in the width direction (W) of the band-shaped rubber member (R), and movement portions that each move each of the plurality of holding portions individually in a front-rear direction of the band-shaped rubber member (R), each of the plurality of holding portions is a suchtion pad to suction a top surface of the band-shaped rubber member (R) and a needle-like body that peenetrates into a position midway in the thickness direction of the band shaped rubber member (R), a displacement of each of the movement portions in the front-rear direction being controlled by the control unit based on the detection data and the target length to adjust a degree of elongation in the front-rear direction at or near a held portion of the band-shaped rubber member (R) held by each of the plurality of holding portions . <EOS>