PURPOSE: To permit the manufacture of uniform liquid droplets by a method in which a dispersion liquid is vibrated in advance and then sprayed while rotating a coaxial cylinder inserted into a reactor tube.

CONSTITUTION: A tube 2 with coaxial shaft 4 is rotatably provided inside a reactor tube body 1. When a different liquid is dispersed into the stream of a liquid-liquid system in the reactor tube 1, the liquid flowing inside the reactor tube 1 is sent to an entrance 7 while turning the tube 2 by a motor 6, while the dispersion liquid is passed through a valve 10 and a vibration chamber 11 to give it a vibration in advance and then sent into the system. Then, liquid aggregates of the same size as the clearance between the reactor tube body 1 and the tube 2 are formed and therefore, uniform liquid droplets can be obtained.