A tire/wheel assembly, wherein a run-flat support body comprising an annular shell having an outer peripheral side as a support surface and an inner peripheral side formed in fork-shaped open legs and elastic rings supporting the end parts of the fork-shaped open legs on a rim is inserted into the hollow part of a pneumatic tire, bent parts are formed at the end parts of the annular shell where the annular shell is connected to the elastic rings, the shape of the elastic ring in a cross section orthogonal to the circumferential direction of the elastic ring is formed into a barrel shape having bulged both side faces, the maximum thickness (A) of the elastic ring in a cross section swelling from a tangential line (L1) extending from the apex (P1) of a hump on the rim so as to abut on the axial inner end (P3) of the bent part is 3 to 6 mm, and the maximum thickness (B) thereof swelling from a tangential line (L2) extending from an intersection (P2) between a line segment (L3) parallel with a tire axis through the centroid of a bead core and the inner surface of the tire bead so as to abut on the axial outer end (P4) of the bent part is 1 to 5 mm.