PURPOSE: To simplify the constitution of a device and to enhance the maintenance properties by turning a cover body around a rotary shaft and providing a flow path of gas which has a coaxial structure to the rotary shaft so that gas is introduced into a filter provided to the cover body.

CONSTITUTION: While supplying the gas set in the prescribed conditions into a chamber 4, coating liquid is coated. A cover body 6 is closably arranged to the upper part of the chamber 4 by turning the cover body 6 around a rotary shaft 7. Further, a filter 8 capable of passing the gas is provided to the cover body 6. Furthermore, the flow path 9 of gas which has a coaxial structure to the rotary shaft 7 is arranged so that the gas is introduced into the filter 8. As a result, the constitution of a device is simplified in comparison with a conventional device and also the maintenance properties are enhanced. Moreover, generation of dust is inhibited and also constraint in design is reduced.