A study on the oxidation mechanism of stibnite was carried out to find out the possibility of its direct smelting. Stibnite sample was brought into the electric tube furnace and the temperature was varied from 700℃ to 1000℃ determine the oxidation rate and the oxidation mechanism of stibnite. The results of this experiment are as follows; 1) The activation energy in the oxidation of stibnite by air is 2.1 ㎉/㏖ and stibnite is oxidized easily. 2) Sb metal is produced during the oxidation of stibnite by air at a temperature higher than 900℃, which suggests the possibility of direct smelting stibnite into metal. 3) Addition of lime accelerates the oxidation rate as the content of lime increases.