A study on the oxidation of stibnite has been carried out using a vertical reactor with N₂-O₂ mixtures of 5 to 20 volumes% at the temperature between 320℃ and 420℃. Possible oxidation mechanism for the reaction has been discussed with the experimental kinetic data obtained in this investigation. To evaluate a rate equation satisfying the data of the reaction, various oxidation kinetic models have been discussed. The results obtained in this work can be summarized as follows; 1) The rate for the oxidation process of stibnite at the temperature between 320℃ are 340℃ was found being controlled by the reaction of O₂with Sb₂S₃at the reaction surface. But the rate, at the temperature between 350℃ and 420℃, was found being controlled predominantly by O₂diffusion through the product layer. 2) The effect of O₂concentration in N₂-O₂mixtures on the oxidation of stibnite decreased as the roasting temperature increased. And also more the O₂concentration in N₂O₂mixtures, less the roasting temperature was effective on the oxidation of stibnite. 3) The rate equation for the oxidation of stibnite showed a good agreement with experimental data.