Abstract: A method for adsorbing harmful substance comprising at least two adsorptive units composed of a plurality of cylindrical or bag-shaped adsorptive elements made of a cloth-like or sheet-like adsorptive material having a 0.1 m/second pressure loss of not more than 15 mm Aq/cm, said adsorptive material consisting predominantly of active carbon fibers having an equilibrated adsorption amount of benzene of not less than 300 mg/g and an adsorption rate constant of benzene of not less than 0.2 /minute, and the ratio of the area of said adsorptive material to the area of the unit frame being not less than 2, and at any one of said adsorptive units, when used for desorbing the adsorbed harmful substances, a heated purging gas jetting device being provided at the upper part of the adsorptive unit.