Experiments of biomass gasification using bench-scale fluidized bed gasifier at 873 K in N-2 and steam were carried out to investigate the effect of catalysts on tar emission abatement and gas composition. At first activated alumina particles and sand were used as bed materials to compare the amounts of tar emission and generated gas compositions. Activated alumina particles were shown to greatly reduce tar emission, which decreased as the ratio of feed rate of activated particles and biomass increased. In gasification tests using eight kinds of nonmetallic catalysts including the activated alumina particles, no differences between the catalysts in the amount of generated gas were found in N-2. On the other hand, in steam gasification as tar emission decreased the amount of generated gas increased due to a catalystic action between tar and steam. It was found that the amount of tar emission and generated gas correlated with the amount of acid sites on the catalysts.