A vehicle body structure comprises: a side roof rail, a rear roof rail, and a rear pillar, which are disposed in the rear portion of an vehicle body, and which intersect each other at an intersecting portion; a rear door provided for optionally opening and closing a rear port of the vehicle body; an automatic opening and closing unit disposed inside the vehicle body and in the vicinity of the intersecting portion; an aperture provided in the intersecting portion; and an arm provided through the aperture for connecting the automatic opening and closing unit to the rear door. The automatic opening and closing unit is fixed to at least the side roof rail, the rear roof rail, and the rear pillar so as to pass above the aperture.