An outsole of a shoe includes: a plurality of ridges having a tread surface to be in contact with a road surface; and at least one longitudinal groove defined between the plurality of ridges. At least in a partial area of each of a forefoot portion and a rear foot portion on a medial side of a foot, the plurality of ridges and the longitudinal groove extend in a longitudinal direction or a diagonal longitudinal direction and are set so that an angle of the ridges and that of the longitudinal groove with respect to a long axis of the outsole are in a range of 0° to 35°. A ratio of a length of the tread surface of the ridges with respect to a width of the tread surface is set to be 1.8 to 200. The width of the tread surface of the ridges is set to be greater than a width of the longitudinal groove by a factor of 2 to 100.