The invention relates to a household biomass gasifying furnace. Biomass fuel is added into the furnace through a feeding port or a burner; after ignition above the biomass fuel, the biomass fuel begins combustion, the oxygen necessary for the biomass to burn is supplied by a primary air inlet at the lower part of the furnace bridge; the combustion state of the biomass can be controlled by controlling the air supply volume, so that the biomass can be gasified. The combustible gas generated by the biomass floats upward by the air in the furnace because the specific weight of the combustible gas is low, mixes with the air input by the secondary-air-intake pipe at the end with smaller diameter of the burner and burns. In the use, just by adjusting the height of the furnace bridge and the air intake of the primary-air-intake port, the effective gasification of the biomass fuel can be guaranteed, and the full combustion of the combustible gas can be guaranteed. It is obvious that for the invention, it is not necessary to collect, clean and transmit the combustible gas from the gasified and combusted biomass, and the invention is free from any tar treatment and overcomes the shortcomings of prior technology. As the gasifying furnace is very easy to operate, one can learn to use the furnace just by a glance, therefore the invention is called ''automatic'' household biomass gasifying furnace.