In a case of multilayer circuit boards where a plurality of conventional films are used as insulating layers, the films are connected with each other using an adhesive, and therefore, the adhesive sometimes negatively affects reduction in thickness. Therefore, a plurality of two-sided boards with films used therein are pasted together with a paste connection layer interposed therebetween, the paste connection layer being configured such that through holes formed in a prepreg are filled in with a conductive paste which is then cured, and second wires are electrically connected with each other through the conductive paste with which the through holes formed in the paste connection layer in advance are filled in, and thus, a multilayer board can be provided without using an adhesive, and the entirety of the multilayer circuit board can be reduced in thickness.