A device for producing an unvulcanized ring-shaped rubber member, the device comprising: a transport conveyor that transports an unvulcanized band-like rubber member toward a forming drum; a front edge arrangement mechanism that holds and disposes a front edge portion (Ra) of the band-like rubber member onto an outer circumferential surface of the forming drum; a rear edge bonding mechanism that holds and bonds a rear edge portion (Rb) of the band-like rubber member to the front edge portion (Ra) on the outer circumferential surface; and a control unit configured to control movement of the transport conveyor, the front edge arrangement mechanism, and the rear edge bonding mechanism, the front edge portion (Ra) and the rear edge portion (Rb) of the band-like rubber member wound around the outer circumferential surface being bonded by a preset allowable bonding margin, the rear edge bonding mechanism comprising a plurality of holding portions arranged side by side in a width direction of the band-like rubber member, and movement portions that individually move each of the holding portions in a front-rear direction of the band-like rubber member, and before bonding the rear edge portion (Rb) to the front edge portion (Ra), the control unit controlling an amount of movement of each of the movement portions in the front-rear direction using distribution data on a length of the band-like rubber member in the width direction, and thus a degree of elongation around a held portion of the rear edge portion (Rb) in the front-rear direction that is held by each of the holding portions being adjusted, characterised in that; the rear edge bonding mechanism comprises a pressing bar disposed on a side of a top surface of the rear edge portion (Rb) and extending in the width direction, the rear edge portion (Rb) is pressed by moving the pressing bar toward the top surface of the rear edge portion (Rb), and thus the rear edge portion (Rb) is bonded to the front edge portion (Ra) on the outer circumferential surface, and wherein a movement velocity of each of the movement portions in the front-rear direction is set at an identical velocity. a transport conveyor that transports an unvulcanized band-like rubber member toward a forming drum; a front edge arrangement mechanism that holds and disposes a front edge portion (Ra) of the band-like rubber member onto an outer circumferential surface of the forming drum; a rear edge bonding mechanism that holds and bonds a rear edge portion (Rb) of the band-like rubber member to the front edge portion (Ra) on the outer circumferential surface; and a control unit configured to control movement of the transport conveyor, the front edge arrangement mechanism, and the rear edge bonding mechanism, the front edge portion (Ra) and the rear edge portion (Rb) of the band-like rubber member wound around the outer circumferential surface being bonded by a preset allowable bonding margin, the rear edge bonding mechanism comprising a plurality of holding portions arranged side by side in a width direction of the band-like rubber member, and movement portions that individually move each of the holding portions in a front-rear direction of the band-like rubber member, and before bonding the rear edge portion (Rb) to the front edge portion (Ra), the control unit controlling an amount of movement of each of the movement portions in the front-rear direction using distribution data on a length of the band-like rubber member in the width direction, and thus a degree of elongation around a held portion of the rear edge portion (Rb) in the front-rear direction that is held by each of the holding portions being adjusted, characterised in that; the rear edge bonding mechanism comprises a pressing bar disposed on a side of a top surface of the rear edge portion (Rb) and extending in the width direction, the rear edge portion (Rb) is pressed by moving the pressing bar toward the top surface of the rear edge portion (Rb), and thus the rear edge portion (Rb) is bonded to the front edge portion (Ra) on the outer circumferential surface, and wherein a movement velocity of each of the movement portions in the front-rear direction is set at an identical velocity.