Production method for impeller

A production method for an impeller which includes a disk which has a disk shape about an axis, a plurality of blades which are formed on a surface facing a first side in an axial direction of the disk with gaps therebetween in a circumferential direction about the axis, and a cover which covers the plurality of blades from the first side in the axial direction and in which a flow path is formed between the disk, the cover, and the blades, the production method comprising:

• an impeller molding body forming step of forming an impeller molding body in which a reinforcement portion which reinforces at least one of end portions of the impeller in which an inlet and an outlet of the flow path are formed and the impeller are integrated with each other, by an additive manufacturing method using a metal powder;
• and
• a removal step of removing the reinforcement portion from the impeller molding body,
• wherein in the impeller molding body forming step, the impeller molding body is formed such that inner peripheral surfaces of the inlet and the outlet of the flow path are inclined with respect to a vertical direction and a horizontal direction.