A rotor balance adjustment method includes: an impeller adjustment process of adjusting, with respect to each of the plurality of impellers, a balance of a position of the center of gravity of the impeller by separately adjusting a weight of the impeller before being attached to the rotor main body; a fixing process of fixing the plurality of impellers to the rotor main body after the impeller adjustment process is performed, wherein the plurality of impellers comprises a large-sized impeller that is larger and heavier than the other impellers; an inclination adjustment process of adjusting an inclination of the large-sized impeller with respect to the rotor main body after the fixing process is performed; and a rotor adjustment process of adjusting a balance of a position of the center of gravity of the rotor.