To provide a continuous polymerization method of a monomer droplet useful for the manufacture of multi-kinds of polymer particles in small quantity, a continuous polymerization apparatus therefore, and a continuous manufacturing apparatus of the polymer particle.

The continuous polymerization method of a monomer droplet for continuously obtaining a polymer particle comprises a step of continuously feeding, into a reaction tube, an emulsion containing a monomer droplet comprising a single kind of monomer or a mixture of a plurality of kinds of monomers while continuously or intermittently feeding a gas in a flow rate of 1-10 vol% relative to the flow rate of the emulsion and a step for causing the monomer droplets in the emulsion to polymerize by irradiating the emulsion with an active energy ray while the emulsion passes through the reaction tube.