NOVELTY - A fuel cell unit (10) has a fuel cell (12), a cooling unit (14), a waste heat recovery system (18), a hot water supply system (22), a modifier (34), a combustor (52), a heat exchanger (68) and a combustion exhaust gas flow path (54). The waste heat recovery system recovers exhaust heat produced from the fuel cell for producing warm water. The hot water supply system supplies warm water to a warm water use apparatus (20). The modifier produces reformed gas and supplies it to a fuel electrode of the fuel cell. The combustion exhaust gas produced by combustion reaction is supplied to the heat exchanger by the combustion exhaust gas flow path.    USE - As an electric power supply.    ADVANTAGE - The fuel cell unit has favorable startability of the fuel cell, and generates electric power easily.    DETAILED DESCRIPTION - The fuel cell unit (10) has a fuel cell (12), a cooling unit (14) to cool the fuel cell, a waste heat recovery system (18), a hot water supply system (22), a modifier (34), a combustor (52), a heat exchanger (68) and a combustion exhaust gas flow path (54). The recovery system recovers exhaust heat produced from fuel cell for producing warm water. The hot water supply system supplies warm water to a warm water use apparatus (20). The modifier produces reformed gas containing hydrogen which is used as a fuel by carrying out modification reaction with a modification catalyst (40), and supplies it to a fuel electrode of the fuel cell. The combustor burns the fuel and heats the modification catalyst. The combustion exhaust gas produced by combustion reaction is supplied to the heat exchanger by the combustion exhaust gas flow path.    DESCRIPTION OF DRAWING(S) - The figure shows the structure of fuel cell unit. (Drawing includes non-English language text)    Fuel cell unit (10)    Fuel cell (12)    Cooling unit (14)    Waste heat recovery system (18)    Warm water use apparatus (20)    Hot water supply system (22)    Modifier (34)    Modification catalyst (40)    Combustor (52)    Combustion exhaust gas flow path (54)    Heat exchanger (68)