A method of manufacturing a build-up printed circuit board, in which the circuit of a build-up printed circuit board including a core layer and an outer layer is realized by forming the metal seed layer of the core layer using a dry process, consisting of ion beam surface treatment and vacuum deposition, instead of a conventional wet process, including a wet surface roughening process and electroless plating. When the wet process is replaced with the dry process in the method of the invention, the circuit layer can be formed in an environmentally friendly manner, and as well, all circuit layers of the substrate including the core layer and the outer layer can be manufactured through a semi-additive process. Further, the peel strength between the resin substrate and the metal layer can be increased, thus realizing a highly reliable fine circuit.