A turbine exhaust system includes an exhaust hood inner casing that involves the turbine rotor; an exhaust hood outer casing that forms an exhaust hood, together with the exhaust hood inner casing; a flow guide that forms an annular diffuser flow path; and exhaust hood upper part flow guides each of which serves as means for separating annular plane upper part exhaust steam within a range including a vertical upward flow out of exhaust steam radially discharging from the flow guide into the exhaust hood, from other exhaust steam, to thereby introduce the separated steam to the condenser, wherein exhaust steam introduction-side end faces thereof are located further toward the upper side than the horizontal plane containing the central axis of the turbine rotor.