NOVELTY - A solid oxide fuel cell is provided with a cylindrical combustion chamber for combusting fuel material. A wall of combustion chamber is defined by cell units and has a composite wall structure comprising at least two wall layers. The innermost wall layer is formed from cell units. The cell units comprise a substrate of solid electrolyte, an anode layer on combustion chamber side of substrate, and a cathode layer on another side of substrate.    USE - The solid oxide fuel cell is useful as an electric source for LED, display LCD, driving potable radios or televisions, and personal digital assistant. It may be used as an electric source for use in outdoor equipment, for emergency purposes and at the time of electric failure.    ADVANTAGE - The inventive solid oxide fuel cell shortens the time for electricity generation and has simple structure. It has reduced size and weight and can be produced at lower production cost. It effectively utilizes a space in the combustion chamber and is easy to maintain.    DETAILED DESCRIPTION - A solid oxide fuel cell comprises cell unit(s) (5) disposed proximate to a flame (6) generated upon combustion of gaseous fuel material and exposed to the flame, thus, creating electricity. The cell units comprise a substrate of solid electrolyte, an anode layer formed on a combustion chamber side of the substrate, and a cathode layer formed on another side of the substrate opposed to the anode layer. The fuel cell is provided with a cylindrical combustion chamber (11) for combusting fuel material. A wall of combustion chamber is defined by the cell units and has a composite wall structure comprising at least two wall layers. The innermost wall layer adjacent to the combustion chamber is formed from the cell units. Air is guided through an air-guiding path formed between the adjacent wall layers. Atmospheric air is supplied to the combustion chamber after flowing through the air-guiding path.    DESCRIPTION OF DRAWING(S) - The figure is a cross-sectional view of the inventive solid oxide fuel cell.    Cell units (5)    Flame (6)    Combustion chamber (11)    Gas burner (16)    Air supplying opening (18)    Air fan (21)    Fuel cell structures (B1-B3)