A multi-layer circuit board capable of reducing an electrical resistance between circuit patterns positioned inside the circuit board and a through-hole connection conductor. A plurality of circuit patterns are superposed on each other with a plurality of insulating layers being alternately interposed therebetween in turn. A solution in which ultrafine metal particles of the independent dispersion type such as silver, gold, palladium or the like are contained in a colloid-like manner is applied so as to extend from one of lands through an inner surface of a through-hole to the other land. Then, the solution is calcined to form a metal particle film, The metal particle film is coated thereon with a conductive paste such as a resin/silver paste or the like, which is then calcined to form a conductive paste layer.