PURPOSE: To obtain such effects as vaporization and concn., cooling, aeration and dedusting by bringing a liq. into efficient contact with a gas.

CONSTITUTION: A method is constituted by using a fan 4 generating a circular air flow, a rotating disc with sawteeth-like projections on its peripheral part for preparing fine and uniform droplets or liq. lines and a power part 2 for rotating them with a high speed. When a liq. is fed from the central part of this disc 3, the liq. is spread into a membrane-like state on the disc by a centrifugal force and it becomes eventually fine and uniform droplets or liq. lines and flys about into the surrounding high speed circular air flow from the projections on the peripheral edge. As the result, retention time in the gas becomes longer and bringing the liq. into contact with the gas is efficiently and rapidly performed.