To provide a CO2 fixing method capable of efficiently absorbing of CO2 to recover CO2 as an industrial raw material and capable of performing absorption and fixation by a low energy.

In the CO2 fixing method, an amine is allowed to act on a first aqueous phase containing salts and CO2 in a gaseous phase is brought into contact with the amine to remove the amine as an amine salt not only to leave cations of salts in the first aqueous phase but also to react the cations with CO2 dissolved from a gaseous phase to form a carbonate. By this method, CO2 is fixed as the carbonate.