<p>It is intended to provide a purification method whereby the efficiency of the purification of polluted soil can be sufficiently elevated by controlling the temperature of the polluted soil even at a low temperature and promoting the activation of an aerobic microorganism capable of decomposing an organic pollutant. Namely, a method of purifying polluted soil which comprises supplying air through soil having been polluted with an organic pollutant, thus activating an aerobic microorganism capable of decomposing the organic pollutant, and decomposing the organic pollutant via fermentation to thereby purify the polluted soil, wherein a fermentation aid containing a rice bran paste is added to the polluted soil and the air supply rate is controlled so as to maintain the temperature of the polluted soil to 10 to 50<SUP>o</SUP>C.</p>
