An impeller element includes a plurality of blades disposed along an outer circumference of a circular support plate. Each blade is divided into a plurality of blade sections in a rotational axis direction. At least one of the divided blade sections as a long-chord blade section is configured such that a chord as a line segment connecting a blade outer-circumferential edge and a blade inner-circumferential edge of the blade in a cross section perpendicular to a rotational axis of the blade has a greater length than a chord of another one of the blade sections as a short-chord blade section. The blade inner-circumferential edge of the at least one long-chord blade section having the longer chord protrudes toward the inner circumferential side, relative to the blade inner-circumferential edge of the at least other one of the blade sections as the short-chord blade section having the shorter chord.