A 300% modulus at 100° C. in the range of 1 mm in an radial direction from a surface of a tread member is set to be between 1.10 times and 2.0 times inclusive, more preferably, between 1.10 times and 1.5 times inclusive, larger than a 300% modulus at 100° C. in the range of 0.5 mm to 1.5 mm in the radial direction from a bottom part of the tread member.