Abstract: Nanoporous carbons were prepared from cypress chips under a flow of superheated steam, and their surface area reached more than 1000m2/g without an additional activation process. Cypress charcoals prepared at a temperature of 800－870℃ had a large external surface area of more than 400m2/g, comparable to the microporous surface area, even though only 30－40m2/g was obtained by carbonization in a flow of Ar gas. Cypress charcoals prepared above 900℃ were microporous with a microporous surface area more than 800m2/g and an external surface area of about 150m2/g. The pore structure in cypress charcoals could be controlled by selecting the temperature of the steam.