Gasification of sawdust was conducted using a circulation system of heat carrier particles, which produced syngas of medium calorific value without using oxygen. The interior of the gasifier used in this experiment, which was made of SUS-316 (a main body of 155 mm in inner diameter and 1.25 m in tube height), was divided into four sections by intersecting two flat vertical plates at right angles. Two sections were used for the upflowing bubbling fluidized beds and the other two sections were used for the incipiently fluidized downcomers. The gasification of sawdust was carried out during fifteen hours without any troubles and the reverse motion of heat carrier particles. The obtained results demonstrated the potential advantages of this gasifier. The gas produced by both pyrolysis and steam gasification of sawdust, which were conducted at approximately 1200 K, was composed of mainly hydrogen, carbonmonoxide, carbondioxide and methane. The total yield of the produced gas of which the higher heating value was 13 MJ/Nm3 on the nitrogen-free basis was approximately 1.0Nm3/kg-dry sawdust on the nitrogen-free basis.