To provide a wheel bolt having improved liquid tightness while making the shape of a flange somewhat free without the need for caulking or welding a cap when mounted, and to provide its manufacturing method.

The cap 20 has a skirt portion 23 which is formed in a sloping shape farther from a cylinder portion 22 outward to the radial direction so as to be opposed to an inclined portion 12b of a flange 12 of a bolt body 10. When the cylinder portion 22 of the cap 20 is pressed into the outer peripheral face of a hexagonal portion 13 of the bolt body 10 with interference fit, the skirt portion 23 is thrust against the inclined portion 12b of the flange 12 of the bolt body 10, elastically deformed and put in close contact along the inclined portion 12b of the flange 12 of the bolt body 10 with the elastic force of the skirt portion 23. A front end 23c of the skirt portion 23 engages with a stepped portion 112c in close contact along the stepped portion 112c of the flange 12 of the bolt body 10.