A liquid (10) stored in a generation chamber (2) is sprayed by an injection nozzle (33) using pressurized gas introduced to it. This strikes a buffer valve (4) where it is atomized. The generated mist is held in the generation chamber (2). The atomized generated mist is introduced into a particle classifier (5) and made to collide with a collision plate (52). The particles of less than 10 μm size bouncing off the collision plate are discharged as a micro-mist from a discharge port (56) and fed to a target workpiece. The large particles deposited on the collision plate are recovered in a generator.