Liquid is sent into the two spray orifices of nozzle tip and is atomized inside the orifices by shearing force. Then, the sheared liquid, when sprayed out from the orifices, is re-atomized by supersonic jet. Each fog stream, sprayed out from the two spray orifices apart, collides with each other in the center and are further atomized by 33,000–40,000 Hz ultrasonic waves. As the result, generated is ultra-fine fog with uniform spray droplets distribution having no large particles.