PURPOSE: To restrain backflow and to increase a mix proportion by introducing a pressurized transport fluid into a Coanda spiral flow generation area due to feed-in of compressed flow.

CONSTITUTION: An introduction pipe 10 for pressure flow such as pressurized air or the like is connected to a pressurized room 2 incorporating a Coanda spiral flow generating device 1, and further the interior of the pressurized room 2 is connected to a hopper 7 through a communicating pipe 11. A compressed flow feed-in pipe 3 is connected to the Coanda spiral flow generating device 1 to generate a Coanda spiral flow. An open end 5 for introducing transport fluid of the generating device 1 is disposed opposite to a discharge port of a rotary feeder 6 of the hopper 7 while the pressurized room 2 is in the pressurized state. In this arrangement, backflow can be restrained so as to transport a fluid with a high concentration.