A steam turbine facility suppresses the possibility of vibration from occurring and prevents a drastic increase in facility cost, thereby realizing an increase in size of the facility, even if steam conditions of 650° C. or higher are adopted. In the steam turbine facility including a high-pressure turbine, an intermediate-pressure turbine, and a low-pressure turbine, the intermediate-pressure turbine is separated into a first intermediate-pressure turbine on a high-temperature and high-pressure side and a second intermediate-pressure turbine on a low-temperature and low-temperature side. At least any one of the rotors and casings of the steam-introduction-side turbines into which steam with a temperature of 650° C. or higher is introduced is formed from Ni-based alloy, and at least any one of the overall rotors and the overall casings of the turbines are constructed by joining together a plurality of rotor members or casing members by welding.