PURPOSE: To eliminate the loss of fuel due to a gas leak and improve the reliability of electrical connection and structural reliability by omitting the seal section of a fuel feed chamber, and forming a current collecting rod into an integral structure with no restriction.

CONSTITUTION: One end of a cylindrical cell 21 is closed by a seal cap 24 with a recess 22a larger than the inner diameter of the cylindrical cell 21 on the inside, and it has a power generation section. The interior of the cap 24 is formed into a double structure, and it is taken into consideration that a current collecting rod is extended by heat and slid downward. A fuel injection tube 26 concurrently serving as a current collecting tube is inserted into the cell 21. The upper end of the tube 26 is suspended on an upper tube plate 27. A vent hole 32 improves the passing of fuel gas to prevent the oxidation of a lead section 39a. The fuel gas 38 sent to a fuel feed chamber 36 passes between the tube 26 and an insulating tube 28 and is 100% fed into the cell 21.