Absorption experiments of H2S into aqueous FeCl3 solutions were performed in an agitated vessel with a flat interface, and the reaction kinetics and mechanism for this system were analyzed using the data of the absorption rates measured over wide ranges of ionic strength, pH and temperature. It was found that the species which reacts with H2S is FeOH2+, and the absorption rates could be explained quantitatively by the theory of gas absorption with an irreversible (1,1)-th order reaction between H2S and FeOH2+. from the comparison with our previous data for a H2S-aqueous Fe-2(SO4)(3) solution system, it wits inferred that the species reacting with H2S in the absorption of H2S into aqueous Fe(III) solutions is FeOH2+, independent of the kind of anion to form iron salt, and the reaction kinetics and skeleton of reaction mechanism are identical.