TIRE

A circumferential narrow main groove extending in a circumferential direction in a tread of a pneumatic tire. The circumferential narrow main groove includes a narrow portion opening to a road contact surface of the tread and a widened portion having a wider groove width than the narrow portion. The widened portion is at a groove bottom. A groove width ratio (W/W) of a maximum groove width W of the widened portion to a groove width W of the narrow groove portion is in a range 1.5≤(W/W)≤4.0, and a cross-sectional area ratio (A/A) of a groove bottom-side cross-sectional area A to a groove opening-side cross-sectional area A in a meridian cross-section is within a range 1.2