PURPOSE: To reduce the amount of gas exhausted to the outside of the system and to reduce the heat loss by equipping a dehumidifier on the midway of the recycling system for recycling the exhaust gas from suction rolls into the dryer hood.

CONSTITUTION: A dehumidifier 8 is equipped in a system for circulating the exhaust gas from suction rolls 3 between dryer rolls 2. The amount of gas exhausted from the system is reduced by the amount of water discharged from the dehumidifier to the outside of the system and the air supply from the outside of the system can also be reduced. The latent heat of the high-humidity exhaust gas, consequently, can also be utilized.