At a run-flat tire, given that an average radius of curvature of a case line between an intersection point (0.1SHp) and an intersection point (0.2SHp) when viewed in a cross-section along a tire rotation axis is radius R1, and that an average radius of curvature of the case line between an intersection point (0.4SHp) and an intersection point (0.6SHp) when viewed in the cross-section along the tire rotation axis is radius R2, ratio R2/R1 is set to be greater than 0.3.