A wheel tread part 2 of a tread is constituted of a longitudinal main groove 3 formed in a circumferential direction via a center of a width direction, a plurality of longitudinal subgrooves 4 formed on both side parts of the longitudinal main groove 3 in the circumferential direction, and a plurality of traverse grooves 5 formed in a width direction to intersect the longitudinal main and subgrooves 3, 4, and divided into a plurality of blocks 6. Each of the plurality of blocks 6 is provided with a one-end-open sipe 9, and formed so that rigidity in the width direction can be higher in an end a of a center side region compared with an end b of a shoulder side region. Since the rigidity of the end a of the center side region is higher, a reaction force is generated in accordance with a steering angle from the start of changing the same.