To enhance ride comfort in normal running without deteriorating run flat durability.

This run flat tire comprises approximate crescent-sectioned side reinforcing rubbers 10 arranged in a side wall area Y and inside in a tire axial direction of a carcass 6. In a tire meridian cross-section including a tire rotary shaft in a no-load normal state where a normal rim is rimmed and a normal internal pressure is packed, in the side wall part 3, thickness W1 at an outer end position P1 in the tire axial direction P1 in the tire axial direction of a belt layer 7, thickness W3 at a tire maximum width position P3, and thickness W2 at an intermediate position P2 between the outer end position P1 and the tire maximum width position P3 satisfy formulae (1)-(3), 0.9W3/W11.1 (1), 0.8W2/W11.0 (2), W2W3 (3).