Bio-oil/char-slurries from fast pyrolysis of woody biomass has received much attention recently, because of its high carbon density and energy density, 5-10 times compared with volumetric wood chip. This paper describes the characteristics of fast pyrolysis of woody biomass as the first stage of study for "bio-oil/char-slurries". The woody biomass, cypress powder and block, are decomposed thermally in a T-tube reactor (φ48IDx640mm horizontally, φ25x280mm vertically) filled with Ar gas of 737 K, and the yield of gas, liquid and solid are discussed. The gas production lasts more long time than 2 second which is regarded as an optimum residence time for bio-oil production.