NOVELTY - The gasifier (20) has a pressure application part (23) for controlling a moving direction of gas by a free convection, which originates in a temperature difference of the gas in a gasifier main body. The gas is generated by applying a pressure in the gasifier main body. A fuel-supply part (21) is provided in order to supply woody biomass in a gasifier (24). The fuel-supply part is attached above a gasifying agent supply part (22) and equipped with a tank (21a), which stores a pellet (80). The gasifying agent supply part is provided in order to supply gasifying agents e.g. air.    USE - Gasifier for gasifying a woody biomass e.g. gas and sawdust such as chip or pellet, in an electric power generating apparatus (claimed).    ADVANTAGE - The gasifier can increase production amount of combustible-gas and a thermal efficiency of the electric power generating apparatus by applying the pressure and controlling the moving direction so that the gas reaches from an upper part of the gasifier to a center area in the gasifier. The gasifier can completely combust the woddy biomass at a short time and easily burn the woddy biomass from a viewpoint of causing incomplete combustion. The gasifier can perform electric power generation of carbon dioxide emissions zero by the woody biomass and a biodiesel fuel and improve supply capacity of a gasifying agent supply part used by a downdraft formula, thus achieving size reduction of the gasifier and the electric power generating apparatus without necessary to attach a large sized apparatus separately as the pressure application part.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:    (1) a woody biomass gasification method    (2) an electric power generating apparatus.    DESCRIPTION OF DRAWING(S) - The drawing shows a block diagram of a gasifier.'(Drawing includes non-English language text)'    Gasifier (20)    Fuel-supply part (21)    Tank (21a)    Gasifying agent supply part (22)    Pressure application part (23)    Gasifier (24)    Pellet (80)