This steam turbine system is provided with a first support rod (41) which is disposed in an outer casing (33) and extends in one direction. The first support rod (41) includes a first end (41A) which is connected to a surface, of an inner surface (45a) of an upper half of an end plate (45), on a first side in a lateral direction of an axial line of a rotor. The first support rod (41) includes a second end (41B) which is connected to an inner surface (48a) of a ceiling plate (48) which is disposed further on a second side in the lateral direction of the outer casing (33) than the first end (41A).