According to one embodiment of the present disclosure, a sealing device of a wheel bearing may be disposed axially outside of rolling elements and may be mounted between an outer ring and a hub. The sealing device of the wheel bearing may comprise an outer ring slinger mounted on the outer ring, a hub slinger mounted on the hub, and a deviation-preventing protrusion which protrudes from an outer circumferential surface of the hub to hold an axial inner end of the hub slinger when the hub slinger moves inward in an axial direction. The outer circumferential surface of the hub may meet the deviation-preventing protrusion at right angles.