Abstract: A vehicle rear body structure includes rear floor panels, rear wheel housings, and rear side extensions. The rear side extensions each have a first joined portion that is joined to a breadthways outer end of each of the rear floor panels, a second joined portion that is joined to an rear end of each of the rear wheel housings, a side portion that is an uprising slanted portion extending from the rear end of the first joined portion to the second joined portion, a surface portion surrounded by the first joined portion, the second joined portion, and the side portion, and an extending portion joined to a flange portion of a rear pillar, wherein the side portion is configured to have higher stiffness or strength than at least the surface portion.

Abstract: A vehicle rear body structure includes rear floor panels, rear wheel housings, and rear side extensions. The rear side extensions each have a first joined portion that is joined to a breadthways outer end of each of the rear floor panels, a second joined portion that is joined to an rear end of each of the rear wheel housings, a side portion that is an uprising slanted portion extending from the rear end of the first joined portion to the second joined portion, a surface portion surrounded by the first joined portion, the second joined portion, and the side portion, and an extending portion joined to a flange portion of a rear pillar, wherein the side portion is configured to have higher stiffness or strength than at least the surface portion.

Abstract: With an excessive impact load generated by a side impact or collision, even in the event that a falling deformation of a pillar connected to a side sill occurs at an initial stage of the side impact, triggering a twisting deformation of the side sill as the side sill is pulled along with the falling deformation of the pillar, the side sill is allowed to maintain a high rigidity against the impact load at a middle stage of the side impact due to a projecting surface of a secondary reinforcement panel being made to be oriented upwards by virtue of the twisting deformation of the side sill.

Abstract: With an excessive impact load generated by a side impact or collision, even in the event that a falling deformation of a pillar connected to a side sill occurs at an initial stage of the side impact, triggering a twisting deformation of the side sill as the side sill is pulled along with the falling deformation of the pillar, the side sill is allowed to maintain a high rigidity against the impact load at a middle stage of the side impact due to a projecting surface of a secondary reinforcement panel being made to be oriented upwards by virtue of the twisting deformation of the side sill.