A manufacturing method of an impeller includes forming a plurality of blades integrally on a blade attachment surface of one of a disc and a cover, placing the cover on a floor so as to face up the blade attachment surface of the cover, disposing the disc on the cover so as to face down the blade attachment surface of the disc, and bonding the plurality of blades to the blade attachment surface of the other of the disc and the cover which is not formed integrally with the plurality of blades by using a bonding material.