<p>There is provided a tapered coupling structure in which a tapered shaft can be coupled to and decoupled from a hub without the use of an O-ring. In a tapered coupling structure 10 in which a tapered shaft 20 and a hub 30 are coupled to each other, the tapered shaft 20 is provided with a taper part 21 on the side of being coupled to the hub 30, and the hub 30 is provided with a high-rigidity part 32 having a thickness in the radial direction larger than that of other regions and having a high rigidity in the radial direction. An oil groove 24 formed in the outer peripheral surface of the taper part 21 to feed oil to the coupling surfaces of the taper part 21 and the hub 3 is provided in a region corresponding to the high-rigidity part 32 in the axial direction.</p>
