A radial force support apparatus includes: a shaft coupled to an impeller and configured to rotate together with the impeller; and a foil radial bearing supporting the shaft. The foil radial bearing includes a top foil disposed on an inner circumferential surface of the foil radial bearing and facing at least a part of an outer circumferential surface of the shaft, and the shaft facing the top foil includes at least one groove provided on the outer circumferential surface of the shaft.