Adsorption properties of wood charcoal prepared by a traditional method are investigated by using CO₂ adsorption at 195 K and N₂ adsorption at 77 K, focusing on the effects of the treatment temperature. The amount of CO₂ adsorbed at 195 K and N₂ adsorbed at 77 K increases with treatment temperature. The shape of the N₂ adsorption isotherm indicates that the charcoal is predominantly characterized by micropores with the presences of mesopores, when high treatment temperature is applied. At a low treatment temperature, the ratio of n_CO2 to n_N2 is high, whereas, it approaches to unity at the higher treatment temperature than 773 K. The adsorption of CO₂ at 195 K can be used for surface area measurement, in place of N₂ adsorption at 77 K, for the charcoal treated higher temperature.