A process for producing a multilayer board includes the steps of applying a bonding ink to the terminal of the first substrate, the bonding ink including a thermosetting resin containing a filler and a curing agent, the filler being formed of metal particles plated with solder, the metal particles each having a first melting point, and the solder having a second melting point lower than the first melting point; bonding the second substrate to a bonding sheet composed of a thermosetting resin and having a through hole disposed in a portion corresponding to the terminal of the second substrate; and heating and pressurizing the first and second substrates with the bonding sheet in such a manner that the terminals are opposite each other to effect curing of the bonding sheet and the bonding ink and to form an integral structure.