In this study, the relationship between the pore size distribution and the adsorption amount of adsorbates is investigated in detail. Adsorption amounts of non-polar adsorbates were greater than those of polar adsorbates because of slight negative charge on surfaces of adsorbents. The adsorption of benzene on the surface of absorbents was largely influenced by the specific pore size of $2{sim}4$ times of benzene diameter. But in case of toluene, the adsorption of toluene was affected by pore sizes of $2{sim}4$ times as well as $4{sim}6$ times of the diameter of toluene. Both acetone and MEK were examined by the same method. The adsorption of acetone was influenced by pore sizes of $2{sim}4$ times of the diameter of acetone. But acetone does not look to be built up multi-layer on those pore sizes. Since acetone molecule is small and its mobility is so fast, it is assumed that the adsorption and desorption of acetone is simultaneously occurred at the same time even at room temperature. In case of MEK, MEK was effected by pore sizes of $2{sim}4$ times of the diameter of MEK.