A rear sub frame comprising a pair of side members, a front cross member, and a rear cross member. The front cross member is configured in substantially a V shape in a front view such that the front cross member slants continuously from both end portions thereof toward a central portion, in a vehicle width direction, thereof which is located below a rear differential, and that a center position, in the vehicle width direction, of a bottom portion of the front cross member which corresponds to an apex portion of the V shape is offset from a center of a vehicle body in the vehicle width direction toward a specified side which matches an offset-arrangement side of a ring gear arranged in the rear differential.