A gas turbine, comprising: a compressor section for compressing air; a combustor for mixing the air compressed by the compressor section and fuel to cause combustion to generate combustion gas; a turbine section for deriving rotational driving force from the combustion gas; and an exhaust section arranged such that exhaust gas discharged from the turbine section flows thereinto, wherein the exhaust section comprises: a casing in which a gas path part is formed; a bearing part that rotatably supports a rotary shaft on which the turbine section is installed; a strut that extends inwardly from the casing and supports the bearing part; a strut cover that extends along the strut to form a space between the strut and the strut cover; an internal diffuser that extends along a rotational axis of the turbine section and surrounds the bearing part so as to form an air space therebetween; an opening formed in the casing; and a cooling flow channel that extends from the opening toward the bearing part along the strut to guide air to the gas path part and opens into the gas path part at a position downstream of a last-stage moving blade of the turbine section, wherein the space between the strut and the strut cover forms a part of the cooling flow channel, characterized in that the air space between the bearing part and the internal diffuser forms a part of the cooling flow channel. a compressor section for compressing air; a combustor for mixing the air compressed by the compressor section and fuel to cause combustion to generate combustion gas; a turbine section for deriving rotational driving force from the combustion gas; and an exhaust section arranged such that exhaust gas discharged from the turbine section flows thereinto, wherein the exhaust section comprises: a casing in which a gas path part is formed; a bearing part that rotatably supports a rotary shaft on which the turbine section is installed; a strut that extends inwardly from the casing and supports the bearing part; a strut cover that extends along the strut to form a space between the strut and the strut cover; an internal diffuser that extends along a rotational axis of the turbine section and surrounds the bearing part so as to form an air space therebetween; an opening formed in the casing; and a cooling flow channel that extends from the opening toward the bearing part along the strut to guide air to the gas path part and opens into the gas path part at a position downstream of a last-stage moving blade of the turbine section, wherein the space between the strut and the strut cover forms a part of the cooling flow channel, characterized in that the air space between the bearing part and the internal diffuser forms a part of the cooling flow channel. a casing in which a gas path part is formed; a bearing part that rotatably supports a rotary shaft on which the turbine section is installed; a strut that extends inwardly from the casing and supports the bearing part; a strut cover that extends along the strut to form a space between the strut and the strut cover; an internal diffuser that extends along a rotational axis of the turbine section and surrounds the bearing part so as to form an air space therebetween; an opening formed in the casing; and a cooling flow channel that extends from the opening toward the bearing part along the strut to guide air to the gas path part and opens into the gas path part at a position downstream of a last-stage moving blade of the turbine section, wherein the space between the strut and the strut cover forms a part of the cooling flow channel, characterized in that the air space between the bearing part and the internal diffuser forms a part of the cooling flow channel.