A fabricating method of a circuit board including the following steps. First, a liquid material is adhered between a first substrate and a second substrate by using an atmospheric pressure difference. Then, a plurality of conductive columns are formed in the first substrate and the second substrate. Next, a patterning process is performed, so as to form two circuit layers. Next, two lamination structures are formed respectively on the circuit layers. Then, the first substrate and the second substrate are separated. Finally, another patterning process is performed, so as to finish the fabrication of the circuit board.