X-ray computed tomography (CT) was used to visualize the intraparticle structure of woody biomass and its chars. Additionally, the impact of the intraparticle structure on gasification characteristics was investigated. The chars derived from ramin (hardwood) and Japanese cypress (softwood) were gasified under an O-2/Ar atmosphere. X-ray CT was used to observe the intraparticle structure. As a result, X-ray CT performed well in visualizing relatively large pores of over 5 mu m. The ramin chars had larger pores aligned along the transverse direction in comparison to Japanese cypress chars. The pores aligned along the grain direction were dominant in both chars. Although the gasification rate of both chars was similar, the impact of the anisotropic intraparticle structure originating from the nature of wood manifested in the evolution of the partide shape during gasification controlled by internal diffusion. This was due to large pores acting as gas transport pathways inside the chars. The gasification advanced along the transverse direction in the ramin chars and resulted in the formation of an ellipse shape, although the initial shape was a cylinder. On the contrary, in the Japanese cypress chars, the gasification progressed only along the grain direction and the cylindrical shape was maintained.