An automobile sub-frame structure for supporting two double wishbone type rear suspensions on its respective sides includes a pair of juxtaposed first members extending in a direction widthwise of a vehicle body, a pair of opposed second members extending substantially vertically and each rigidly secured at an upper portion thereof to one end of each first member, and a pair of third members rigidly secured to lower portions of the second members and to a lower surface of a central portion of each first member. In the sub-frame structure, a plurality of truss structures are formed by the first, second and third members so that the sub-frame structure will be sufficiently rigid. Each double wishbone type rear suspension includes upper and lower control arms for pivotably supporting a rear wheel, which control arms are pivotably connected at their inner ends to the second members in the vicinity of portions connecting the first and second members and in the vicinity of portions connecting the second and third members, respectively.