NOVELTY - The fuel-cell assembly comprises a housing, a cell stack, a catalyst storage case (78a), a gas-introduction unit (82a), and a gas-deriving unit (80a). A modification catalyst (102a) and/or a de-sulfurization catalyst are accommodated in the case. A source gas introduced to the case through the gas-introduction unit receives action of catalyst and is supplied to cell stack through gas-deriving unit. A temperature detector (105) and/or pressure sensor are provided in the case and are connected to the measuring device besides the housing.    USE - For distributed-type electric-powder generation for domestic use (both claimed).    ADVANTAGE - The fuel-cell assembly enables acquisition of optimal catalyst environment even when the production of electricity is fluctuated according to the electric-power demand and when the catalyst storage case is heated with combustion gas. Functional deterioration of the fuel cell by thermal-impact destruction and crack is suppressed, and durability is improved.    DETAILED DESCRIPTION - The fuel-cell assembly comprises a housing which prescribes a generator room, a cell stack arranged in the housing, a catalyst storage case (78a) arranged in the housing, a gas-introduction unit (82a) attached to the catalyst storage case, and a gas-deriving unit (80a) attached to the catalyst storage case. A modification catalyst (102a) and/or a de-sulfurization catalyst are accommodated in the catalyst storage case. A source gas introduced to the catalyst storage case through the gas-introduction unit receives the action of the catalyst and is supplied to the cell stack through the gas-deriving unit. A temperature detector (105) and/or a pressure sensor are provided in the catalyst storage case and are connected to the measuring device besides the housing.    DESCRIPTION OF DRAWING(S) - The figure shows the partial cross-section of the catalyst storage case.    Catalyst storage case (78a)    Gas-deriving unit (80a)    Gas-introduction unit (82a)    Modification catalyst (102a)    Temperature detector (105)