A fuel cell module comprising: a fuel cell stack formed by stacking a plurality of fuel cells for generating electricity by electrochemical reactions of a fuel gas and an oxygen-containing gas; a reformer for reforming a mixed gas of water vapor and a raw fuel chiefly containing hydrocarbon to produce the fuel gas supplied to the fuel cell stack; an evaporator for evaporating water, and supplying the water vapor to the reformer; a heat exchanger for raising a temperature of the oxygen-containing gas by heat exchange with a combustion gas, and supplying the oxygen-containing gas to the fuel cell stack; an exhaust gas combustor for combusting the fuel gas discharged from the fuel cell stack as a fuel exhaust gas and the oxygen-containing gas discharged from the fuel cell stack as an oxygen-containing exhaust gas to produce the combustion gas; and a start-up combustor for combusting the raw fuel and the oxygen-containing gas to produce the combustion gas, wherein the fuel cell module includes: a first area where the exhaust gas combustor and the start-up combustor are provided; an annular second area around the first area and where the reformer and the evaporator are provided; an annular third area around the second area and where the heat exchanger is provided, and wherein a stress relaxing portion for relaxing heat stress is provided at least along a border between the first area and the second area, along a border between the second area and the third area, or along an outermost circumferential portion of the third area. a fuel cell stack formed by stacking a plurality of fuel cells for generating electricity by electrochemical reactions of a fuel gas and an oxygen-containing gas; a reformer for reforming a mixed gas of water vapor and a raw fuel chiefly containing hydrocarbon to produce the fuel gas supplied to the fuel cell stack; an evaporator for evaporating water, and supplying the water vapor to the reformer; a heat exchanger for raising a temperature of the oxygen-containing gas by heat exchange with a combustion gas, and supplying the oxygen-containing gas to the fuel cell stack; an exhaust gas combustor for combusting the fuel gas discharged from the fuel cell stack as a fuel exhaust gas and the oxygen-containing gas discharged from the fuel cell stack as an oxygen-containing exhaust gas to produce the combustion gas; and a start-up combustor for combusting the raw fuel and the oxygen-containing gas to produce the combustion gas, wherein the fuel cell module includes: a first area where the exhaust gas combustor and the start-up combustor are provided; an annular second area around the first area and where the reformer and the evaporator are provided; an annular third area around the second area and where the heat exchanger is provided, and wherein a stress relaxing portion for relaxing heat stress is provided at least along a border between the first area and the second area, along a border between the second area and the third area, or along an outermost circumferential portion of the third area. a first area where the exhaust gas combustor and the start-up combustor are provided; an annular second area around the first area and where the reformer and the evaporator are provided; an annular third area around the second area and where the heat exchanger is provided, and wherein a stress relaxing portion for relaxing heat stress is provided at least along a border between the first area and the second area, along a border between the second area and the third area, or along an outermost circumferential portion of the third area.