To make the amount of air to a telescopic chute less when a pneumatically transported powder is thrown to a storage tank through the telescopic chute.

A powder exit 26 of a cyclone 25 is connected to an upper end of an inner cylinder 9 of the telescopic chute 6 of double cylinder structure formed by expandable/contractable inner cylinder 9 and outer cylinder 11. A pneumatic transportation line 1 is connected to the cyclone 25. An air discharge pipe 29 of the cyclone 25 is connected to a dust collector 31 through an air discharge line 32. An air removal out line 22 connected to the outer cylinder 11 is connected to the air discharge line 32. After the pneumatically transported powder 2 in the air transport line 1 is separated from conveying air 27 in the cyclone 25, it is passed through the inner cylinder 9 of the telescopic chute 6 and is dropped off/thrown to the storage tank 4 of a transport vehicle. The air 8 in the storage tank 4 replaced with the powder 2 thrown is led to the air discharge line 32 through an air removal out flow passage 12 between the inner and outer cylinders of the telescopic chute 6 and the air removal out line 22 and dust collection treatment is carried out with the conveying air 27 in the dust collector 31.