An outsole is formed of a viscoelastic body containing a rubber component. This viscoelastic body has a loss factor measured by a dynamic viscoelasticity measurement under conditions of a temperature of 23° C., a frequency of 10 Hz, a static strain of 10%, and a dynamic strain of 7% being 0.17 or more, a storage elastic modulus measured by the dynamic viscoelasticity measurement being 5.7 MPa or less, and a ratio of a tensile stress at 300% elongation to a tensile stress at 100% elongation being 4.4 or more. Such outsole is excellent in wet grip performance and durability.