In a vehicle rear body structure in which a muffler is disposed below a rear cross member disposed to extend transversely below a rear part of the body of a vehicle, a lower end portion 10 of the rear cross member 7 extends downwardly to substantially the same height of that of a lower end portion 4c of a rear bumper face 4a disposed rearward of the rear cross member. Accordingly, it is possible to prevent the generation of heat deformation by protecting from heat related effects from a muffler a lower end portion of a rear bumper which tends to easily heat deform.