A drying device that includes a drying furnace having an inlet and an outlet, a drying unit installed inside the drying furnace and for drying a to-be-dried object, a number of upper and lower rolls alternately arranged at internal top and bottom portions of the drying furnace, and a roll driver connected to the plurality of upper and lower rolls and moving the upper rolls upwardly and the lower rolls downwardly, wherein after the to-be-dried object is transferred from the inlet to the outlet, the roller driver moves the upper rolls downwardly, moves the lower rolls upwardly, or moves the upper rolls downwardly and the lower rolls upwardly.