Provided is an impeller in which a through hole is provided in a center of a base member of the impeller and a plurality of recessed parts are formed on a bottom surface of the base member. Meanwhile, a jig using in a cutting work of the impeller includes a seating part having a seating surface, a shaft part is erected from a central part of the seating part and is engageable with the through hole of the impeller, and protruded parts are formed on the seating surface and are engageable with the recessed parts provided on the base-member bottom surface of the impeller.
