In a wrinkling prevention device, a work roll having a diameter smaller than that of a press-roll is pressed against the press-roll, and the work roll is supported by a bearing frame through a backup. With this configuration, an uncoated part can be elongated with a uniform pressing force. Further, an edge roller is disposed at an end part of the bearing frame which supports the work roll, and the edge roller is brought into contact with the other press-rolls not in contact with the work roll so that the axis parallelism of the work roll with the press-roll can be ensured.