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.degree. 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.degree. 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/mm.sup.2 or more; the rotor shaft is made from a ferrite based forged steel having a 10.sup.5 h creep rupture strength of 11 kgf/mm.sup.2 or more; and the inner casing is made from a ferrite based cast steel having a 10.sup.5 h creep rupture strength of 10 kgf/mm.sup.2 or more.