A method for manufacturing an impeller of a centrifugal rotary machine in which the impeller is formed from one block, the impeller having a disk-shaped disc around an axis line (Ar), a plurality of blades disposed on an outer peripheral surface of the disc to be spaced apart from each other in a circumferential direction (Dc) with respect to the axis line (Ar); and a cover which sandwiches the plurality of blades between the disc and the cover, a flow path being formed between the disc and the cover and between the plurality of blades, the flow path causing the fluid flowing in from an axial direction front side (Daf) which is one side in an axial direction (Da) in which the axis line (Ar) extends, to flow outward in a radial direction (Dro) with respect to the axis line (Ar), the method comprising: executing a flow path-cutting process of cutting a flow path region serving as the flow path in the block using a plurality of types of tools that are different from each other, wherein the flow path-cutting process comprises a rough cutting process of cutting using a rough cutting tool which is one of the plurality of tools, and a residue-cutting process of cutting the cutting residue in the rough cutting process using a residue-cutting tool which is one of the plurality of tools, each of the plurality of tools used in the flow path-cutting process has a tool main body having a blade formed at least on an outer periphery around a tool axis line (At), and a handle to which the tool main body is fixed, and which is long in a tool axis direction (Dta) in which the tool axis line (At) extends, around the tool axis line (At), a maximum outer diameter of the tool main body in the residue-cutting tool is larger than a minimum outer diameter of the handle in the residue-cutting tool, and the tool main body in the residue-cutting tool has a rear blade directed in a direction including a tool rear side component which is a side of the handle with respect to the tool main body in the residue-cutting tool, the method being characterised in that an overhanging amount, which is a distance from an outer peripheral surface at a position which is a minimum outer diameter of the handle to a position having a maximum outer diameter of the outer periphery of the tool main body in a direction perpendicular to the tool axis line (At), is maximum in the residue-cutting tool among the plurality of tools. executing a flow path-cutting process of cutting a flow path region serving as the flow path in the block using a plurality of types of tools that are different from each other, wherein the flow path-cutting process comprises a rough cutting process of cutting using a rough cutting tool which is one of the plurality of tools, and a residue-cutting process of cutting the cutting residue in the rough cutting process using a residue-cutting tool which is one of the plurality of tools, each of the plurality of tools used in the flow path-cutting process has a tool main body having a blade formed at least on an outer periphery around a tool axis line (At), and a handle to which the tool main body is fixed, and which is long in a tool axis direction (Dta) in which the tool axis line (At) extends, around the tool axis line (At), a maximum outer diameter of the tool main body in the residue-cutting tool is larger than a minimum outer diameter of the handle in the residue-cutting tool, and the tool main body in the residue-cutting tool has a rear blade directed in a direction including a tool rear side component which is a side of the handle with respect to the tool main body in the residue-cutting tool, the method being characterised in that an overhanging amount, which is a distance from an outer peripheral surface at a position which is a minimum outer diameter of the handle to a position having a maximum outer diameter of the outer periphery of the tool main body in a direction perpendicular to the tool axis line (At), is maximum in the residue-cutting tool among the plurality of tools.