A center pillar section formed of a high-tensile steel plate is fixed to a side panel frame section including a roof rail section formed of an ordinary-tensile steel plate. A reinforcing member formed of a high-tensile steel plate is provided inside the roof rail section, and the center pillar section is fixed at its upper end portion to the outer surface of the reinforcing member and at its lower end portion to the side sill section. A door beam provided within a front door overlaps the center pillar section and lower portion of a front pillar section. Front and rear end portions of the door beam are opposed to respective increased-width portions of the front pillar section and center pillar section.