A method for controlling a particle diameter and a particle diameter distribution of emulsion particles during manufacturing of an emulsion dispersion is provided. The method includes causing two or more types of liquids substantially immiscible with each other to continuously and sequentially pass through net bodies. The net bodies are disposed in a cylindrical flow passage at intervals of 5 to 200 mm, and the number of the net bodies is more than 50 and 200 or less. Each of the net bodies is equivalent to a gauze having a mesh number of 35 mesh to 4000 mesh in accordance with an ASTM standard and has a surface that intersects the direction of the flow passage. An emulsification apparatus used for the method includes a feed pump for feeding two or more types of liquids substantially immiscible with each other and a cylindrical flow passage to which the two or more types of liquids fed by the feed pump are delivered. A predetermined number of net bodies are disposed in the cylindrical flow passage at predetermined intervals, and each net body has a surface intersecting the direction of the flow passage.