A rear bumper structure includes a lower side member at both sides of a vehicle parallel to a length direction of a floor panel and below the floor panel, an upper side member at both sides of the vehicle parallel to the length direction of the floor panel and above the floor panel and connected to the lower side member by a rear cross member, a bracket having a first end fixed to the lower side member and a second end extending in a bent form toward the rear of the vehicle, a bumper having a first end hinge-coupled to the second end of the bracket and a second end extending in a bent form from the first end toward an outside of the vehicle, and a crash box fixed to the second end of the bumper and coupled to the upper side member.