NOVELTY - A multi-stage firewood burning stock gas cooker comprises a firewood burning room (3); a firewood inlet (2); a cooker grate (1) in front of the burning room; a gas guiding port (4) at the back part of the burning room; and fuel gas rooms (5). The burning and gas rooms of two to three stages at back side are arranged as one list at lengthways direction on the ground. They are connected by the respective guiding port. A lower part of each gas room has an ash outlet (6). An upper part at back side of the gas room of the final stage has a wind suction device (7).    USE - A multi-stage firewood burning stock gas cooker for drying grain, wooden meal and particulate matters.    ADVANTAGE - The multi-stage firewood burning stock gas cooker utilizes fuel that uses residual material in bamboo or wooden processing or other combustible refuse; utilizes waste; protects the environment; generates stock gas at the same time of burning firewood and generating heat and then grades and burns the stock gas; stores heat in each room so that burning is adequate; and has high heat yield, uniform and lasting heat supply.    DETAILED DESCRIPTION - A multi-stage firewood burning stock gas cooker comprises a firewood burning room (3); a firewood inlet (2); a cooker grate (1) in front of the burning room; a gas guiding port (4) at the back part of the burning room; and fuel gas rooms (5). The burning room and the gas rooms of two to three stages at back side are arranged as one list at lengthways direction on the ground. The burning room and the gas rooms are connected by the respective gas guiding port. An inner top wall (8) of each of burning and gas rooms is transversely arc shaped. A lower part of each fuel gas room is provided with an ash outlet (6). An upper part at back side of the fuel gas room of the final stage is provided with a wind suction device (7), i.e. a chimney or an air pump. The firewood burning room has an inner height of 90-120 cm, an inner width of 100-180 cm, and an inner depth of 150-200 cm. Each stage of the gas room has an inner height of 70-100 cm, an inner width of 100-180 cm, and an inner depth of 200-300 cm. Mouth height of each gas guiding port is 30-40 cm.    DESCRIPTION OF DRAWING(S) - The drawing is a side sectional view of the multi-stage firewood burning stock gas cooker.    Cooker grate (1)    Firewood inlet (2)    Firewood burning room (3)    Gas guiding port (4)    Fuel gas rooms (5)    Ash outlet (6)    Wind suction device (7)    Inner top wall (8)