A pneumatic tire to be mounted on a rim, comprises a pair of bead portions each having a bead core therein, wherein in a meridian section of the tire under a non-mounted state that the tire is not mounted on the rim but the bead portions are held such that the bead width is equal to the rim width of the rim, each bead portion has a profile comprising a bead base extending between a bead toe and a heel-side point, the bead base comprising an axial base width, a straight part extending from the bead toe toward the heel-side point having an inclination so that an extended line thereof passes through the heel-side point, a convex part provided between an axially outer end of the straight part and the heel-side point and protruding radially inside of the extended line, and the convex part having a radius of curvature of from 0.20 to 0.33 times the base width and a height from the extended line of from 0.067 to 0.13 times the base width.