Giant reed (Arundo donax) is a perennial, gramineous plant that has high biomass production potential. In this study, we focused on its applicability as a raw material for the production of adsorbents for the purification of cadmium-contaminated water. Charcoals were prepared from the stalk of the giant reed at various temperatures (400 - 700°C) under nitrogen stream. Analysis of pore size distribution based on methanol vapor adsorption revealed that the mesopores within the range of 20 to 100 Å were abundant in charcoals prepared under 400°C and 500°C. Using these charcoals, the removal capacity of cadmium from aqueous solution was investigated. As a result, high removal capacity under low concentration of cadmium was observed. High yield of cadmium with 0.01 N hydrochloric acid treatment was also clarified. X-ray diffraction (XRD) analysis revealed that Cd(OH)₂ existed on the surface of the cadmium-adsorbed charcoal. The possible mechanism of the "apparent adsorption" was discussed.