The present invention relates to a tire capable of suppressing the cracks of the groove bottom surfaces of shoulder main grooves and therefore suppressing the tears of the shoulder land regions. A tire comprises a tread portion (2) comprising a shoulder main groove (5) extending on a side of a tread edge (Te) and comprising inner and outer groove walls (11) and (12). The inner groove wall (11) hasan angle [theta]1 with respect to a tread normal line in a cross section of the shoulder main groove periodically increasing and decreasing in a tire circumferential direction so as to comprise concave and convex wall portions (16) and (17) arranged alternately in the tire circumferential direction. The outer groove wall (12) has an angle [theta]2 with respect to a tread normal line in the crosssection periodically increasing and decreasing in the tire circumferential direction so as to comprise convex and concave wall portions (22) and (21) arranged alternately in the tire circumferential direction. The angle [theta]2 is larger than the angle [theta]1 in any cross section of the groove.