a circuit board essentially comprises a first laminated structure , at least a first plated through hole , at least a second laminated structure , a middle dielectric layer and at least a second plated through hole is disclosed . the first laminated structure has at least three first circuit layers and at last two first dielectric layers . the first circuit layers and the first dielectric layers are alternately laminated and any two adjacent first circuit layers have a first dielectric layer disposed between them . the first plated through hole passes through the first laminated layer . the second laminated structure is laminated over the first laminated structure . the middle dielectric layer is disposed between the first laminated structure and the second laminated structure . the second plated through hole passes through the first laminated structure , the middle dielectric layer and the second laminated structure .