NOVELTY - The container (11) has a substrate (1) with a concave portion in which a fuel modifier (9) is accommodated. A cylindrical metal fitting (3) is inserted through a through-hole formed in the substrate or the cover component, while fixing the lead terminal inside the cylindrical metal fitting. The fitting is joined to the substrate or cover, as a space is formed between the outer and inner surfaces of the through-hole.    USE - For accommodating fuel modifier in fuel reformer (claimed) used in fuel cell systems useful as power-supply systems of portable apparatuses, such as mobile telephones, notebook personal computers, digital camcorders, and digital still cameras.    ADVANTAGE - The container maintains the fuel modification temperature of the fuel modifier, and reduces the electric-power-generation loss. The transmission of heat from the lead terminal to the substrate is decreased. The container provides fuel cell systems which can be used stably and safely for a long period of time.    DETAILED DESCRIPTION - The container (11) has a substrate (1) with a concave portion in which a fuel modifier (9) which generates reformed gas containing hydrogen gas from a fuel, is accommodated. A discharge pipe (5b) connects an exterior in the concave portion for emitting the reformed gas from the fuel modifier. A supply pipe (5a) connects an exterior in the concave portion for supplying fuel to the fuel modifier. The container comprises a lead terminal which penetrates the substrate or a cover component (4), for supplying electricity to the fuel modifier. A cylindrical metal fitting (3) is inserted through a through-hole formed in the substrate or the cover component, while fixing the lead terminal inside the cylindrical metal fitting through a sealing agent. The metal fitting is joined to the substrate or the cover, as a space is formed between the outer surface and the inner surface of the through-hole.    An INDEPENDENT CLAIM is included for fuel reformer.    DESCRIPTION OF DRAWING(S) - The figure shows the sectional drawing of the container.    substrate (1)    cylindrical metal fitting (3)    cover component (4)    supply pipe (5a)    discharge pipe (5b)    fuel modifier (9)    container (11)