To provide a new sole structure wherein a protruding section is provided on the insole surface of a shoe to improve a flatfoot, and at the same time, the concentration of a pressure to a specified section of the sole of the foot is reduced against a grounding impact.

A foot sole contact section (protruding section) 4 of a specified shape is formed on a curved member (wire). Then, a tensile stress or a compressive stress is applied to the curved member, and under a state wherein the foot sole contact section is projected to the foot sole side, both end sections in the direction by which the tensile stress or the compressive stress is applied are fixed to the sole member of a footwear. Also, a fixing section is provided at both end sections which are fixed.