Pneumatic tire

A pneumatic tire is provided in the tread portion 2 with a main groove 10 and an axial groove 20. The groove-sidewall surface 16 on each side of the main groove 10 is formed by a circular-arc-like surface having a radius R1 of curvature and being convex to the groove center 10c side. The groove-sidewall surface 26 on each side of the axial groove 20 is formed by a circular-arc-like surface having a radius R2 of curvature and being convex to the groove center 20c side. The radius R2 of curvature of the groove-sidewall surface 26 of the axial groove 20 is more than the radius R1 of curvature of the groove-sidewall surface 16 of the main groove 10.