The experiment of the preparation of active carbon was carried out from next three sorts of charcoals, 1) Hard charcoal ( Quercus sp.) 2) Soft charcoal (P ines sp. Betula sp.) 3) Hardened or softened charcoal by the carbonization method ( Fagus sp. etc.). 1. Used steam, 20cc, activation temp. 950°C, activation time 5min. used charcoal, 5g, charcoal granule 10_??_20 mesh. 2. Before the activation, the charcoal is pretreated with boiled water, or boiled hydrochloric acid (2%) for 1 hr. 3. Yield; 1) Hard charcoal, non treat 0_??_24% washed with HCI 32_??_38% washed with boiled water 2_??_32% 2) Soft charcoal, non treat 24_??_44% washed with HCI 26_??_46% washed with boiled water 23_??_42% 3) Hardened or Softened charcoal, non treat 28_??_38% washed with HCI 16_??_38% washed with boiled water 26_??_44% The results obtained showed that the charcoal of large volume density was, highly activated than those of small volume density.