To provide a car body rear structure capable of improving the design quality by improving the appearance quality, securely preventing a back door from being damaged when a light load is inputted from the rear of a car body, and restraining increase of body weight and the number of components for supressing the cost increase.

The back door 10 for opening a cabin R backward is provided at the rear of the car body S so as to be freely opened/closed. A bumper 20 extended to the car-width direction is provided at a lower side of the back door 10. The back door 10 comprises an inner panel 11 positioned at a cabin R side when it is closed and an outer panel 12 provided on the outside of the inner panel 11. The outer panel 12 and the bumper 20 are made to smoothly continue to be positioned nearly in flush, and an elastic part 13 bending to the vertical direction is formed at a lower edge part 10a of the back door 10.