Abstract: In the process for reforming a biomass in accordance with the present invention, a mixture of a biomass and water as a raw material is compressed by a compressing pump 2 to be deposited into the inlet side of a circulating pump 43 in a primary reactor 41. The mixture is discharged from the circulating pump 43, conveyed to a heater 45, and then heated at a temperature ranging from 200 to 260° C., and sent to a reacting bath 47. In the reacting bath 47, hemicellulose contained in the biomass dissolves in hot water and subjected to a carbonizing reaction. The mixture derived from the primary reactor 41 is deposited in the inlet side of a circulating pump 44 of a secondary reactor 42, and sent to a heater 46, heated here at a temperature ranging from 270 to 330° C., and sent to the reacting bath 47. In the reacting bath 47, cellulose contained in the biomass dissolves in hot water, and is subjected to a carbonizing reaction.