The dispersion mechanism of emulsion in a static mixer, "Bunsankun", by a disk-type element was made clear and its characteristics were investigated. The static mixer is a compact mixer that can create emulsion of any required size in the range of 1-600 mu m by changing the flow velocity and the hole diameter of element. The static mixer disperses emulsions by repetition of division, combination, shearing and cavitation. The relations of pressure drop and flow velocity emulsion size and flow velocity were expressed by experimental equations. The static mixer can create excellent emulsions.