For both up-flow and down flow gasifiers, pyrolysis process is the main process for volatile and charcoal generation. Therefore, investigations into understanding the pyrolysis process is particularly important in the design of up-flow and down flow gasifier. Basic experiments of biomass pyrolysis were conducted and fundamental data of pyrolysis process were accumulated. The productions of pyrolysis were ash, pitch, charcoal, liquid tar and gas. The total heating value of pyrolysis gas was 10,720 kJ/kg, while the heating value of liquid tar was 17,700 kJ/kg. In order to obtain valuable liquid fuels from liquid tar, atmosphric fractional distillations were conducted. Distilled liquid tar which was obtained at the lowest distillation temperature was yellowish and the heating value was 25,500 kJ/kg. This distilled liquid tar was mixed with diesel fuel and used for diesel engine. It was found that engine power decreased with the increase of mixing ratio.