Automobile rear body structure

aaaaAn automobile rear body structure capable of allowing a space created between a rear bumper reinforcing member and a line connecting respective rear ends of a pair of rear side frames to be effectively utilized. In this automobile rear body structure, a rear end cross member has an expanded portion formed to expand rearward relative to respective rear ends of a pairs of rear side frames, and a rear floor pan has a rear edge including a protruded portion. The protruded portion is formed to protrude relative to the rear ends of the pairs of rear side frames toward the expanded portion of the rear end cross member and connected to the rear end cross member, so as to allow a luggage compartment space to be enlarged rearward relative to the rear ends of the pairs of rear side frames.