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 heat exchanger includes an annular oxygen-containing gas supply chamber to which the oxygen-containing gas is supplied, an annular oxygen-containing gas discharge chamber to which the heated oxygen-containing gas is discharged, heat exchange pipes connected to the oxygen-containing gas supply chamber at one end, and connected to the oxygen-containing gas discharge chamber at another end, and a combustion gas channel for supplying the combustion gas to a space between the heat exchange pipes; an end of an oxygen-containing gas inlet pipe for guiding the oxygen-containing gas to the oxygen-containing gas supply chamber is provided in the oxygen-containing gas supply chamber; a plurality of first inlet holes extend through an axial end surface of the oxygen-containing gas inlet pipe in an axial direction, and a plurality of second inlet holes extend through a circumferential end surface of the oxygen-containing gas inlet pipe radially; and a total area of openings of the first inlet holes is smaller than a total area of openings of the second inlet holes. 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 heat exchanger includes an annular oxygen-containing gas supply chamber to which the oxygen-containing gas is supplied, an annular oxygen-containing gas discharge chamber to which the heated oxygen-containing gas is discharged, heat exchange pipes connected to the oxygen-containing gas supply chamber at one end, and connected to the oxygen-containing gas discharge chamber at another end, and a combustion gas channel for supplying the combustion gas to a space between the heat exchange pipes; an end of an oxygen-containing gas inlet pipe for guiding the oxygen-containing gas to the oxygen-containing gas supply chamber is provided in the oxygen-containing gas supply chamber; a plurality of first inlet holes extend through an axial end surface of the oxygen-containing gas inlet pipe in an axial direction, and a plurality of second inlet holes extend through a circumferential end surface of the oxygen-containing gas inlet pipe radially; and a total area of openings of the first inlet holes is smaller than a total area of openings of the second inlet holes.