PURPOSE: To provide a manufacturing method of constituted parts of a turbine and a steam turbine rotor optimizing a life extending characteristic of the steeple region of the rotor.

CONSTITUTION: This constituted parts of a steam turbine such as a rotor disk, are provided with a ring member composed of a low alloy ferrous metal having ≤about 6 wt.% alloy components and a ferrous graded layer 12 disposed on the ring member and containing plural layered welded parts increasing the wt. ratio of the layer formed metal containing Cr. On this ferrous graded layer, a steeple part alloy 14 containing Cr is disposed in order to optimize a life extending characteristic of the steeple 30 region of the constituted parts of the turbine.