To remove foreign matters (feather of birds) contained in biomass as a raw material and to supply the biomass not containing the foreign matters to a crusher.

The foreign matter removing apparatus 1 for the biomass is used in a biomass gasification system including a raw material supply means provided with a raw material tank 4 for storing the biomass 35 and a crushing means for crushing the biomass 35 supplied from the raw material tank 4 and a gasification means for generating a fuel gas by gasifying the biomass supplied from the raw material supply means, and removes the foreign matters contained in the biomass 35 supplied from the raw material tank 4 to the crushing means. The foreign matter removing apparatus 1 includes an agitation means 8 rotatably provided in the raw material tank 4, and a catching means 12 which is provided integrally with the agitation means 8, is rotatable integrally with the agitation means 8, and catches the foreign matters 36 contained in the biomass 35 inside the raw material tank 4 when rotated.