A data management method for managing data relating to an elongated body wound around a cylindrical member by using a support device for supporting the cylindrical member around which is wound the elongated body, the support device comprising: a support shaft, supported by a support body in a cantilevered state, for supporting the cylindrical member that is fitted to an external surface of the support shaft from an opening on one end in a longitudinal direction of the cylindrical member; an anchoring means, built into the support shaft, for anchoring the cylindrical member from an inner circumferential side of the cylindrical member; an operating means comprising a shaft part smaller in diameter than the support shaft, the shaft part protruding forward from a distal end of the support shaft where a side on which the support shaft is supported in the cantilevered state is defined as a proximal end and where an opposite side thereto is defined as the distal end, the shaft part being arranged to switch between anchoring of the cylindrical member by the anchoring means and releasing thereof; and a protecting member which is attached to the distal end of the support shaft and through which is inserted the shaft part, the protecting member further comprising a reduced-diameter section smaller in diameter than the support shaft, the method comprising: fitting the cylindrical member to an external surface of the support shaft from the opening on one end in the longitudinal direction of the cylindrical member; and performing data communication between a data communication means and a data carrier member which is disposed in a carrier disposition area, where an inner circumferential surface of such a portion of the cylindrical member as is positioned in front of the proximal end of the reduced-diameter section is defined as the carrier disposition area. a support shaft, supported by a support body in a cantilevered state, for supporting the cylindrical member that is fitted to an external surface of the support shaft from an opening on one end in a longitudinal direction of the cylindrical member; an anchoring means, built into the support shaft, for anchoring the cylindrical member from an inner circumferential side of the cylindrical member; an operating means comprising a shaft part smaller in diameter than the support shaft, the shaft part protruding forward from a distal end of the support shaft where a side on which the support shaft is supported in the cantilevered state is defined as a proximal end and where an opposite side thereto is defined as the distal end, the shaft part being arranged to switch between anchoring of the cylindrical member by the anchoring means and releasing thereof; and a protecting member which is attached to the distal end of the support shaft and through which is inserted the shaft part, the protecting member further comprising a reduced-diameter section smaller in diameter than the support shaft, the method comprising: fitting the cylindrical member to an external surface of the support shaft from the opening on one end in the longitudinal direction of the cylindrical member; and performing data communication between a data communication means and a data carrier member which is disposed in a carrier disposition area, where an inner circumferential surface of such a portion of the cylindrical member as is positioned in front of the proximal end of the reduced-diameter section is defined as the carrier disposition area. fitting the cylindrical member to an external surface of the support shaft from the opening on one end in the longitudinal direction of the cylindrical member; and performing data communication between a data communication means and a data carrier member which is disposed in a carrier disposition area, where an inner circumferential surface of such a portion of the cylindrical member as is positioned in front of the proximal end of the reduced-diameter section is defined as the carrier disposition area.