To provide a joint structure capable of suitably joining members which compose the joint structure, and to provide a joining method thereof. The joint structure includes a shaft member, and a cylindrical member an inner surface of which is fitted to an outer surface of the shaft member. The cylindrical member includes first crimped portions which are crimped along axial grooves provided in an axial direction of the shaft member; and a second crimped portion which fits the axial grooves and is crimped along a circumferential groove, the circumferential groove being provided on a circumferential surface of the shaft member by reducing a diameter of an axially intermediate portion in a radial direction.