Abstract: A roll charged with a heat transfer medium includes a heater which is easy to replace and measures by which the temperature in the axial direction of the roll can be kept uniform during operation. A hollow portion of the roll, which can be opened to the atmosphere, is located at a central axial portion of the roll. The heater is a rod-shaped heater and extends along the central longitudinal axis of the hollow portion. Metal having a low melting point is provided between the heater and an inner peripheral surface of the hollow portion. A heat transfer medium is charged in the hollow portion at the periphery thereof. The heat transfer medium may contact a circumferential part of the heater. In addition, a spiral groove or fin may be provided on an internal surface of the hollow of the portion of the roll body that is charged with the heat transfer medium.