A pneumatic tire comprising a shoulder rib segmented into a main rib located at the inner side thereof in a width direction of the tire and a thin rib located at the outer side thereof in the width direction of the tire by a thin groove extending along a circumferential direction of the tire, wherein the thin groove includes a large-width portion having a relatively larger groove width and a small-width portion having a relatively smaller groove width continuously formed one after the other along the circumferential direction of the tire, and an inner wall of the large-width portion located at the thin rib side is disposed at a further outer side with respect to an inner wall of the small-width portion located at the thin rib side as viewed in the width direction of the tire, a protruding portion protruding outwardly in the width direction of the tire from an edge line of the thin rib located at the outer side in the width direction of the tire is formed at a position where the large-width portion is disposed in the circumferential direction of the tire.