A circuit board structure includes a substrate, a third dielectric layer, a fourth dielectric layer, a first external circuit layer, a second external circuit layer, a conductive through hole, a first annular retaining wall, and a second annular retaining wall. The conductive through hole penetrates through the third dielectric layer, a second dielectric layer, and the fourth dielectric layer. The conductive through hole is electrically connected to the first external circuit layer and the second external circuit layer. The first annular retaining wall is disposed in the third dielectric layer, surrounds the conductive through hole, and is electrically connected to the first external circuit layer and the first inner circuit layer. The second annular retaining wall is disposed in the fourth dielectric layer, surrounds the conductive through hole, and connects to the second external circuit layer and the second inner circuit layer electrically.