The liquefaction of ligneous biomass by a hot compressed water method was studied for the utilization of useful biomass components. The pulverized ligneous biomass powder, which diameter was around 10 to 20 micrometer, was used as the raw material for the liquefaction process. In previous paper, it was found that the reactivity and extractability of biomass components were dramatically increased with decreasing the particle diameter. In this study, microwave was used for the heating wood slurry instead of heater. The microwave heating system can be controlled the heating period and reaction period easily and can be expected the decomposition or extraction reaction by microwave itself. In this experiment, the effect of microwave on the generated was component with the generated component at various temperature and reaction period. As the results, total yield of the liquefaction material was not different, but the produced computer of the liquefaction material were different between those heating system.