To prevent the scattering of dust and to enhance the efficiency of filter cloth replacing work.

An apparatus main body casing 17 is constituted of upper and lower surface plates 13, 14 respectively having filter cloth insertion ports 2, the upper cylindrical body 15 connecting the upper and lower surface plates 13, 14 and the lower cylindrical body 16 connecting the part of the filter cloth insertion port 12 of the lower surface plate 14. The lower end part of a filter cloth recovering bag 21 is tightly fixed to the auxiliary cylinder 20 provided to the part of the filter cloth insertion port 12 of the upper surface plate 13 and the upper end part of the filter colth recovering bag 21 is tightly fixed to the outer periphery of a hanging-up fixture 23. A vacuum suction device is connected to the air suction port 24 provided to the upper surface plate 13 and scattered dust is sucked by the vacuum suction device while filter cloth 4 is pulled out along with a retainer 6 by the hanging-up fixture 23.