To improve the working environment around a worker and of the whole shop facility by exhausting the compressed air used in compressing the casting sand, collecting it outside, dust-removing the casting sand and particles from the collected exhausted air, and emitting the dust-removed air into the atmosphere through a silencer.

When the molding of a mold is completed, the air containing the casting sand and its particles is left behind in a cover case 8 and a riser frame 5, and the air is fed as the exhaust air to a dust-removing apparatus 15 by opening an air exhaust pipe 12 through an exhaust air duct 13. The air circulating in the casting sand S is exhausted from a vent hole 7 in a carrier plate 3, and fed as the exhaust air to the dust-removing apparatus 15 from a hollow guide provided on a table 2 through the exhaust air duct 13. The casting sand and its particles contained in the exhaust air fed from two routes to the dust-removing apparatus 15 are separated and removed. The purified air is emitted into the atmosphere through a silencer 16.