NOVELTY - The device has a biomass thermal decomposition zone which heats biomass in a non-oxidizing gas atmosphere, or the mixed gas atmosphere of non-oxidizing gas and steam. A gas reforming zone heats the gas emitted in decomposition zone in presence of steam, to generate pyrolysis gas. The heated granules and lumps (3) are moved from reforming zone to decomposition zone, to reform pyrolysis gas and to perform thermal decomposition biomass using the heat possessed by granules and lumps. A partitioning plate (7) is provided between the biomass thermal decomposition zone and gas reforming zone.    USE - Gasifier device used for producing hydrogen gas from biomass such as plant-derived biomass, living-system biomass, lifestyle coarse discharge biomass and a foodstuff waste material biomass (all claimed), and for generating electric power.    ADVANTAGE - Since the pyrolysis gas emitted in the thermal decomposition zone cannot move to a gas reforming zone through inner pipe, the obstruction such as tar, dust adhered to pyrolysis gas when entrains to a pipe-interior wall cannot be occurred. The heat carrier adhered in an inner pipe cannot be occurred. The pyrolysis gas can pass through the inside of heat carrier layer and raises, so that the tar and dust can be adhered on the surface of the heat carrier effectively and heat of a heat carrier can be decomposed. Hence the gasification efficiency can be improved. The tar and dust without being decomposed can be discharged from the container lower portion with heat carrier. The heat carrier can be added without passing inner pipe between the thermal decomposition zone and a gas reforming zone, the heat loss of heat carrier can be reduced. Hence the thermal efficiency of gasifier can be improved. The material usage-amount of device can be reduced, the device can be miniaturized, and cost reduced.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the gasifier device.    Container (1)    Preheater (2)    Granules and lumps (3)    Biomass supply port (4)    Partitioning plate (7)