A vehicle body structure in which left and right side frames (22, 22) are positioned on both sides in a vehicle-width direction. The left and right side frames have end sections (22a, 22a) on an external-force action side for receiving a collision load (fs) acting from outside the vehicle in a front-rear direction of the vehicle body, and end sections (22b, 22b) on an opposite side from the end sections on the external-force action side. A plurality of fragile sections (81, 81, 82, 82, 83, 83) are provided in each of the left and right side frames. The plurality of fragile sections comprise at least left and right first fragile sections (81, 81) positioned at the end sections on the external-force action side, and left and right second fragile sections (82, 82, 83, 83) positioned apart from the left and right first fragile sections toward the end part on the opposite side. The area (A1) of the left and right first fragile sections is larger than the areas (A2, A3) of the left and right second fragile sections.