A device for sealing joining surfaces of a split rim in a wheel. The split rim comprises an outboard rim and an inboard rim. A joining surface of the outboard rim is formed at its outer periphery with an annular recess of L-shaped section. The annular recess has a bottom surface formed at its base portion with a peripheral groove which receives therein an inner periphery of a seal ring. A joining surface of the inboard rim has at its outer peripheral portion an annular projection of a stepped-like section. The depth of the annular recess is shorter than the sum of the diameter of the seal ring and the thickness of the inner annular projection.