A turbine ventilation structure is provided with: an exhaust gas diffuser (33) for forming an annular exhaust gas passage between an inner cylinder and an outer cylinder, the exhaust gas passage allowing exhaust gas from a turbine to pass therethrough; a strut (47) extending across the exhaust gas diffuser from a housing (19) outside the outer cylinder and supporting a bearing inside the inner cylinder; a strut cover (49) disposed in the exhaust gas passage and covering the outer periphery of the strut; and a connection member (43) disposed in the exhaust gas passage at a position downstream of the strut cover, the connection member (43) having a hollow section and connecting the housing and the inner cylinder. The housing is provided with a first introduction opening (51) for introducing air from the outside. The strut cover has a discharge hole (55) provided at the rear end thereof. The turbine ventilation structure is further provided with a first ventilation passage (VP1) leading from the first introduction opening through the hollow section of the connection member, the first ventilation passage (VP1) further leading from the inner end of the strut through the space between the strut and the strut cover and coming out of the discharge hole into the exhaust gas passage.