A shoe sole comprising: an outsole having a tread surface; and a midsole arranged on the outsole, wherein: the midsole includes an upper layer and a lower layer each of a foamed material; the upper layer is a low-hardness foamed material having a thermoplastic resin component; the lower layer is a high-hardness foamed material that has a thermoplastic resin component and has a high hardness that is higher than a hardness of the low-hardness foamed material; the upper layer is seamlessly and integrally continuous from a posterior end portion ( Rr) of a rear foot portion to an anterior end portion ( Ff) of a forefoot portion; the lower layer is seamlessly and integrally continuous from the posterior end portion ( Rr) of the rear foot portion to a posterior end portion ( Fr) of the forefoot portion; a boundary line, which is a line of an anterior end of the lower layer and is an anterior-posterior boundary between the upper layer and the lower layer, is arranged at the posterior end portion ( Fr) of the forefoot portion; in the forefoot portion, a lower surface of the upper layer includes a primary tread portion between a medial edge portion and a lateral edge portion of the midsole, and a line of a posterior end of the primary tread portion is defined by the boundary line; in the primary tread portion of the forefoot portion anterior to the boundary line, an upper surface of the outsole is attached to the lower surface of the upper layer; and the low-hardness foamed material of the upper layer is made from a low-hardness, high-resilience material having a higher specific gravity than the high-hardness foamed material, the low-hardness, high-resilience material having a low hardness that is lower than the hardness of the high-hardness foamed material, and the low-hardness, high-resilience material having a higher speed at which to recover to an original shape after being deformed than that of the high-hardness foamed material. the midsole includes an upper layer and a lower layer each of a foamed material; the upper layer is a low-hardness foamed material having a thermoplastic resin component; the lower layer is a high-hardness foamed material that has a thermoplastic resin component and has a high hardness that is higher than a hardness of the low-hardness foamed material; the upper layer is seamlessly and integrally continuous from a posterior end portion ( Rr) of a rear foot portion to an anterior end portion ( Ff) of a forefoot portion; the lower layer is seamlessly and integrally continuous from the posterior end portion ( Rr) of the rear foot portion to a posterior end portion ( Fr) of the forefoot portion; a boundary line, which is a line of an anterior end of the lower layer and is an anterior-posterior boundary between the upper layer and the lower layer, is arranged at the posterior end portion ( Fr) of the forefoot portion; in the forefoot portion, a lower surface of the upper layer includes a primary tread portion between a medial edge portion and a lateral edge portion of the midsole, and a line of a posterior end of the primary tread portion is defined by the boundary line; in the primary tread portion of the forefoot portion anterior to the boundary line, an upper surface of the outsole is attached to the lower surface of the upper layer; and the low-hardness foamed material of the upper layer is made from a low-hardness, high-resilience material having a higher specific gravity than the high-hardness foamed material, the low-hardness, high-resilience material having a low hardness that is lower than the hardness of the high-hardness foamed material, and the low-hardness, high-resilience material having a higher speed at which to recover to an original shape after being deformed than that of the high-hardness foamed material.