A mid sole arranged on an outsole having a tread surface, wherein: the mid sole has an upper layer and a lower layer; in the lower layer, one or two or more of an area of a front foot portion greater than or equal to one half of a planar area of the front foot portion, an area of a middle foot portion greater than or equal to one half of a planar area of the middle foot portion, and an area of a rear foot portion greater than or equal to one half of a planar area of the rear foot portion includes a layer of a first foamed body having a thermoplastic resin component; in the upper layer, one or two or more of the area greater than or equal to one half of the planar area of the front foot portion, the area greater than or equal to one half of the planar area of the middle foot portion, and the area greater than or equal to one half of the planar area of the rear foot portion, in which the layer of the first foamed body is arranged, includes a layer of a second foamed body having a thermoplastic resin component; the first foamed body and the second foamed body have different mechanical properties from each other; in one of the three areas, a thickness of the first foamed body differs between a medial side and a lateral side of a foot, and in the area where the thickness of the first foamed body differs, a thickness of the second foamed body differs between a medial side portion and a lateral side portion supporting a reverse side of the foot; a tapered portion whose thickness changes as the tapered portion extends from the medial side to the lateral side is provided between the medial side portion and the lateral side portion in the upper layer; wherein: the layers of the first and second foamed bodies (N,S) are arranged at least in the area greater than or equal to one half of the planar area of the rear foot portion; in the rear foot portion, the layer of the second foamed body has a greater average thickness on the lateral side of the foot than on the medial side thereof; in the rear foot portion, the layer of the first foamed body has a greater average thickness on the medial side of the foot than on the lateral side thereof; and the first foamed body has a greater asker C hardness than the second foamed body (s), characterized in that a rate of change in the thickness of the tapered portion is greater than a rate of change in the thickness of the medial side portion or a rate of change in the thickness of the lateral side portion. the mid sole has an upper layer and a lower layer; in the lower layer, one or two or more of an area of a front foot portion greater than or equal to one half of a planar area of the front foot portion, an area of a middle foot portion greater than or equal to one half of a planar area of the middle foot portion, and an area of a rear foot portion greater than or equal to one half of a planar area of the rear foot portion includes a layer of a first foamed body having a thermoplastic resin component; in the upper layer, one or two or more of the area greater than or equal to one half of the planar area of the front foot portion, the area greater than or equal to one half of the planar area of the middle foot portion, and the area greater than or equal to one half of the planar area of the rear foot portion, in which the layer of the first foamed body is arranged, includes a layer of a second foamed body having a thermoplastic resin component; the first foamed body and the second foamed body have different mechanical properties from each other; in one of the three areas, a thickness of the first foamed body differs between a medial side and a lateral side of a foot, and in the area where the thickness of the first foamed body differs, a thickness of the second foamed body differs between a medial side portion and a lateral side portion supporting a reverse side of the foot; a tapered portion whose thickness changes as the tapered portion extends from the medial side to the lateral side is provided between the medial side portion and the lateral side portion in the upper layer; wherein: the layers of the first and second foamed bodies (N,S) are arranged at least in the area greater than or equal to one half of the planar area of the rear foot portion; in the rear foot portion, the layer of the second foamed body has a greater average thickness on the lateral side of the foot than on the medial side thereof; in the rear foot portion, the layer of the first foamed body has a greater average thickness on the medial side of the foot than on the lateral side thereof; and the first foamed body has a greater asker C hardness than the second foamed body (s), characterized in that a rate of change in the thickness of the tapered portion is greater than a rate of change in the thickness of the medial side portion or a rate of change in the thickness of the lateral side portion. the layers of the first and second foamed bodies (N,S) are arranged at least in the area greater than or equal to one half of the planar area of the rear foot portion; in the rear foot portion, the layer of the second foamed body has a greater average thickness on the lateral side of the foot than on the medial side thereof; in the rear foot portion, the layer of the first foamed body has a greater average thickness on the medial side of the foot than on the lateral side thereof; and the first foamed body has a greater asker C hardness than the second foamed body (s), characterized in that a rate of change in the thickness of the tapered portion is greater than a rate of change in the thickness of the medial side portion or a rate of change in the thickness of the lateral side portion.