An impeller of a centrifugal fluid-type rotary machine includes impeller blades each having a concave and convex surface of which the shape is formed of parallel generatrices inclined with respect to a rotary shaft by an angle defined for each impeller blade. A method of manufacturing the impeller includes inclining a main plate material of the impeller with respect to a plane of a table of a machine tool by a desired angle, fixedly mounting the plate on the table after placing the plate on a rotation indexable jig, controlling three axial positions of the plate in the right and left, front and rear and upper and lower direction by a three-axis controller and cutting out the main plate or side plate by a cutting tool to integrally form the impeller blades on the plate.