The impeller wheel is rotatably supported about a central axis and has a hub on which vanes are arranged. The vane has across its radial length at least similar profiled sections, viewed in cylindrical section through the vane. The radial outermost profiled section which is positioned on a cylindrical enveloping surface of the impeller wheel has a greater displacement relative to the neighboring profiled section than this neighboring profiled section to its neighboring profiled section. The impeller wheel can also be provided on the radial outer edge with at least one projecting flow element whose axial height has a maximum in the area of the leading edge and of the trailing edge of the vane. The impeller wheels, while having a simple constructive configuration, provide a great noise reduction in operation of the ventilator.