In a center pillar structure, the strength of a center pillar is locally low at a weak portion and at a weak portion. Thus, when a vehicle is hit on the side, the center pillar bends at the weak portion and at the weak portion, and the other vehicle advances substantially horizontally. This can reduce the bending moment generated in the center pillar due to advancement of the other vehicle, so it is possible to control deformation of the center pillar in the event of a side collision while ensuring the strength of the center pillar.