The present provides a method for preparing resin fine particles of a homogeneous particle size used in the fields of chemistry, medicine, electronic material or the like, resin fine particles, and a production apparatus for resin fine particles.The present invention provides a method for preparing a resin fine particle, which comprises discharging a liquid comprising a polymerizable monomer as a dispersion phase into a continuous phase; splitting the liquid comprising the polymerizable monomer by applying mechanical vibration to form a liquid droplet; and polymerizing the liquid droplet in a state without splitting or integrating the liquid droplet, said method comprising recognizing a state of said liquid being split into a liquid droplet, and a condition of said discharging and/or said mechanical vibration of the liquid being determined by feedback from a result of the recognition.