PURPOSE: To reduce the power required for drying a strip so as to make temperature control and maintenance easier, by installing a blower to a circulating duct line which supplies a high-temperature gas from an air heating furnace to a drying chamber and returns the gas of the drying chamber to the air heating furnace.

CONSTITUTION: A strip 11 running in the direction shown by the arrow 12 is sent to a drying chamber 14 after it is washed in a washing tank 13. The hot air from a air heating furnace 17 is supplied 20 with a pressure to the chamber 14 through a duct line 18 and blower 19. The gas which is used for drying the strip 11 in the chamber 14 is supplied 21 to a mist separator 22, where water drops and dust are removed from the gas, and returned to the furnace 17 through a duct line 17. During this period, air is supplied to the furnace 17 and a gaseous fuel is supplied with a pressure to a high-pressure gas burner 27 installed to the furnace 17 from a duct line 28. When the drying device of this invention is sued, the pressure loss can be minimized and the power required for operating the blower can be reduced, because the necessity of heat exchanger with fin which is required in the preceeding technique is eliminated.