A compact steam turbine power-generation plant has a compact steam turbine that operates at a high temperature in a range of 600 to 660° C. Ferrite based heat resisting steels provide for thermal efficiency. The main steam temperature and the reheated steam temperature can be set in a range of 600 to 660° C. by making the main parts exposed to the high temperature atmosphere, such as the rotor shaft, from ferrite based forged steels and cast steels and by making a final stage blade of a low pressure turbine from a martensite steel. The final stage blade is made from a ferrite based forged steel having a tensile strength of 120 kgf/mm2 or more; the rotor shaft is made from a ferrite based forged steel having a 105 h creep rupture strength of 11 kgf/mm2 or more; and the inner casing is made from a ferrite based cast steel having a 105 h creep rupture strength of 10 kgf/mm2 or more.