STEAM TURBINE

A steam turbine 10 of an embodiment includes: a nozzle box 30 having a circular ring-shaped steam passage 27 into which steam is led from a steam inlet pipe and having, on a downstream portion of the steam passage 27, a plurality of first-stage nozzles 24a in a circumferential direction; and a second-stage nozzle side structure 40 combined with the nozzle box 30 and having a plurality of at least second-stage nozzles 24b in a circumferential direction. Further, in the respective nozzle box 30 and second-stage nozzle side structure 40, there are provided at least a pair of abutment surfaces for sealing which are not parallel to a turbine rotor axis and abutting each other. Furthermore, a seal member 50 is provided in a part of a gap between the nozzle box 30 and the second-stage nozzle side structure 40, the gap being formed by combining the nozzle box 30 and the second-stage nozzle side structure 40.