This is the method in which contaminant is removed by using the principle in which gas that contains organic solvent gets adhered after coming into contact with active carbon. Organic solvent and inorganic alkali gas are absorbed by using the fact that the active carbon’s porosity is high and that the absorption capability is outstanding. When the active carbon exceeds absorption limit at this time, there is the instance in which active carbon is eliminated. Moreover, there is another method in which organic solvent and water are regenerated when it comes to the liquid that is condensed in the condenser after detaching from the active carbon after heating up as a vapor when the absorption material is organic solvent. At this time, the method in which solute is eliminated when it had powerful adhesiveness power in the low concentration level is viable.