PROBLEM TO BE SOLVED: To provide a treatment system and method for effectively using biomass resources, with which biomass resources are treated in stages, methane gas and hydrogen gas are efficiently formed/recovered without leaving a final residue, especially expensive pyroligneous acid and a hard carbonized product (carbonized material) having excellent gas adsorptivity is formed/recovered. SOLUTION: The treatment system 1 is equipped with a low-temperature carbonization apparatus 2 with which biomass resources comprising a plant, a livestock product, fish and shellfish or their wastes or sewage such as garbage or excreta of a livestock product, etc., are heated in a non-oxidizing atmosphere at >320°C and≤400°C to form pyroligneous acid, methane gas and a carbonized product-containing residue and pyroligneous acid and methane gas are fractionated and removed and a high-temperature carbonization apparatus 3 with which the carbonized product-containing residue formed by the low-temperature carbonization apparatus 2 is heated at >580°C and≤1,000°C to generate a carbonized product and hydrogen gas and the carbonized product and the hydrogen gas are fractionated and recovered. COPYRIGHT: (C)2005,JPO&NCIPI