In order to examine soil adsorption behavior of fluorescein, adsorption-equilibrium experiments were carried out. The soil samples used in this study are Kuroboku soil, Yellow brown forest soil, Kanuma soil and Peat. The parameters on the experiments were the initial concentration of sodium fluorescein (0.1, 1, 10 mg/l) and the mass ratio of soil to liquid (0.001, 0.01, 0.1). When the mass ratio were 0.001 and 0.1, the quantity of fluorescein adsorbed on soils was Kuroboku ≒ Yellow brown forest > Peat >> Kanuma. However, the adsorbed amount on Kanuma was remarkably small and there was not so different among the adsorbed amounts on the other soils. The particle size of soils did not affect the absorbed amount. The BET specific surface area was ranged as Kanuma > Yellow brown forest > Kuroboku > Peat. The absorbed amount on Kanuma having the largest BET specific surface area was the least. Therefore the number of the pore effectively utilized for the adsorption of fluorescein seems to be dependent on the type of soil. The clear correlation could not be found between absorbed amount of fluorescein and each chemical composition which constitutes the soils. It is found that the soil adsorption behavior of fluorescein can be prescribed in the Freundlich's adsorption equation. The adsorption behaviors on Kuroboku, Yellow brown forest and Peat are independent of the initial concentration of fluorescein and the mass ratio of soil to liquid. Although the adsorption behavior on Kanuma is dependent on the mass ratio of soil to liquid, the behavior could be represented by one Freundlich's adsorption equation if the mass ratio is constant.