To easily clean a filter without disassembling, to prevent clogging of the filter even when it is left as it is for a long time without cleaned, and to easily replace the filter.

This air supply and exhaust opening comprises an air supply and exhaust opening body 2 forming an air passage, an air volume adjusting portion adjusting the volume of flowing air by opening and closing the air passage, and composed of a fitting wall 6 of the air supply and exhaust opening body 2 and a flange 44 of a cover 41, the cover 41 for controlling the adjustment of the air volume in the air volume adjusting portion, the filter 32 disposed in the air passage, and a brush 22 kept into contact with the filter 32 for cleaning the same. The cover 41 is connected with a filter body 31 through a pin receiving sleeve and a pin body 37 of the filter body 31, the air passage is opened and closed by controlling the cover 41, and the filter 32 is relatively moved to the brush 22 to be cleaned.

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