Measurements have been done on the rates of carbon and oxygen transfers between CO-CO₂ mixtures and levitated iron droplets. Supposing that the mass transfer between two phases determines the total reaction rate, the kinetics of this reaction has been considered. Results obtained here are as follows: The form of the reaction in the initial period is different from that in the later period. In the initial, simple absorption of gas takes place independently of the composition of the gas mixture. The rate is controlled by the mass transfer at the melt side. In the later period, decarburization or carburization proceeds and the countercurrent flow of CO and CO₂ in the gas phase controls the total rate. It is concluded that whether iron is melted by the levitation technique or in usual crucibles, there are no essential differences in the mechanism of the reaction, and that one or both of the mass transfers at gas and melt determines the total rate of the reaction according to the experimental conditions such as the flow rate and composition of gas, mass and violency of stirring of melt.