A hardened portion in a vehicle structure has an almost hemispherical shape around a lower surface side of a bottom wall rear portion in a vehicle upper-lower direction, the lower surface side serving as a center of a curvature. As the hardened portion is formed, a direction of tensile stress generated in the hardened portion is a radial direction in which the center of the curvature serves as a center side. Thus, occurrence of tensile stress in directions opposite to each other by which a specific part within the hardened portion is pulled apart in a direction orthogonal to the thickness direction of the bottom wall rear portion is inhibited.