To achieve low-cost production in a torsional damper including a hub 1 having a structure in which a hub body 11 is connected with a boss 12, and to reduce swinging during rotation.

A torsional damper includes: a hub 1 mounted to a rotary shaft while an inner diameter part is fastened in an axial direction; an annular mass body 2 arranged concentrically with the hub 1; and an elastic body 3 elastically connecting the hub 1 with the mass body 2. The hub 1 comprises a hub body 11 being a press-formed body and a boss 12 overlaid on the inner diameter part of the hub body 11 in the axial direction. A plurality of radial positioning protrusions 13 brought into close contact with an outer peripheral surface of the boss 12 and a plurality of support spring parts 14 elastically brought into contact with the outer peripheral surface of the boss 12 are formed at the hub body 11 along a circumference concentric with the hub body 11 at predetermined intervals in the circumferential direction. The boss 12 is held by a radial positioning protrusion 13 and the support spring parts 14 concentrically with the hub body 11.