A pneumatic tire comprises main grooves 1 extending in the tire circumferential direction formed in a tread, wherein the main groove 1 has a plurality of narrow grooves 11 in its sidewalls 3, an end portion 11a of the narrow groove 11 on the tread side does not open to the tread surface and is located closest to the tread side, an end portion 11b of the narrow groove 11 on the groove bottom side does not open to the groove bottom 1b of the main groove 1 and is located closest to the groove bottom side, a length L1 of the narrow groove 11 measured in the depth direction of the main groove is 50 to 80% of a depth D of the main groove 1, the narrow groove 11 has at least one or more bend portions 21, and a length L2 of the narrow groove 11 measured along the narrow groove 11 itself is not less than 1.03 times and not more than 2 times L1.