A co-precipitation reactor for manufacturing a positive electrode active material precursor for a secondary battery, the co-precipitation reactor including a reaction chamber having a plurality of suppliers configured to direct a reaction material and a pH adjusting material into the reaction chamber, a stirrer configured to be disposed in the reaction chamber, a drive motor configured to rotate the stirrer, a stirring shaft configured to receive power from the drive motor and rotate the stirrer, a first heater configured to heat an outside of the reaction chamber to heat the reaction material and the pH adjusting material, and a second heater configured to heat an inside of the reaction chamber to heat the reaction material and the pH adjusting material.