PURPOSE: To provide a continuous polymerization apparatus whose cost is decreased by simplifying processes, by arranging a specified single-shaft stirring apparatus and a specified double-shaft stirring apparatus one on the other, providing a connecting pipe between the stirring apparatuses, and integrating them.

CONSTITUTION: This continuous polymerization apparatus comprises a single-shaft stirring apparatus having a substantially horizontal type cylindrical container body and a double-shaft stirring apparatus having an approximately horizontal type cylindrical container body which are arranged one on the other and a connecting pipe arranged between the single-shaft stirring apparatus and the double-shaft stirring apparatus, where the single-shaft stirring apparatus, the double-shaft stirring apparatus, and the connecting pipe are integrated. Preferably, the connecting pipe of the continuous polymerization apparatus is provided with a flow rate control valve. The connecting pipe of the continuous polymerization apparatus has preferably such a structure that, in the upper stage thereof, the overflow from a stirring chamber goes to the connecting pipe, then the overflow flows to the bottom of a well section in the lower stage, and the overflow from the well section flows into the stirring chamber, so that the upper stage and the lower stage are closed with the process liquid.