To securely prevent the dew-condensation inside a casing of a conveyer and to improve the durability and reliability of the conveyer.

The conveyer 1 has a belt B stretched inside the casing 2 and a drive unit 8 for driving to rotate the belt, and a load is carried by rotating the belt B in the casing 2. The conveyer 1 also has a suction blower 16 and an air supply blower 17 as a ventilation unit for ventilating the inside of the casing 2, a temperature sensor 21 and a humidity sensor 22 for detecting the dew-point temperature inside the casing 2, an atmospheric temperature sensor 23 for detecting the atmospheric temperature outside the casing 2, and a control device 50. The control device 50 operates the suction blower 16 and the air supply blower 17 based on the deviation T between the atmospheric temperature Ta detected by the atmospheric temperature sensor 23 and the dew-point temperature Th obtained from the value detected by the temperature sensor 21 and the humidity sensor 22.