A side reinforcing rubber layer includes a second rubber portion having a modulus constant between a boundary surface and a bead portion and larger than a first rubber portion arranged on a tread-portion-2 side. The boundary surface intersects outer and inner surfaces of the side reinforcing rubber layer at first and third points, respectively. The first and third points are arranged on the bead-portion side of second and fourth points, respectively, which are closest points to an outer end of a belt layer of the outer and inner surfaces, respectively. A distance between an inner end of the first rubber portion and the second point is larger than a distance between the second point and the first point.