Method for producing multilayer wiring circuit board

A method of producing a multilayer wired circuit board that can provide sufficient adhesion strength of the interface between a conductor layer and a thermosetting adhesive layer laminated, to provide improvement in connection strength between the conductor layers and thus improvement in reliability. In this method, after a thermosetting adhesive layer is formed on a first conductor layer, an opening is formed in the thermosetting adhesive layer and solder powders are charged in the opening at normal temperature. Sequentially, a second conductor layer is formed on the thermosetting adhesive layer including the opening filled with the solder powders. Thereafter, the solder powders are melted by heating, to electrically connect between the first conductor layer and the second conductor layer.