The purpose of the present invention is to provide an automobile frame having good stiffness. The automobile frame (1) provides a closed cross section formed by welding a flange (3a) of a frame part (3) having a hat-shaped cross section to a panel part (5) facing the flange (3a). Characteristically, the welding is performed by continuous one-side welding at positions (X) defined using a coordinate system in which an end of contact between the flange (3a) and the panel part (5) is an origin (0), an outer end side of the flange (3a) is (-), and a vertical wall side of the hat-shape is (+), by the formula: +v(2Ra-a2)=X>1.5, R=2, where R (mm) denotes the radius of an arc-shaped part (3c) between a hat-shaped vertical wall part (3b) and the flange (3a), and a (mm) denotes the amount of a gap that can be welded.