A circuit board assembly includes an electrical component mounted on or in the assembly; a conductive layer, which is electrically connected to the electrical component; a high-temperature dissipation resin, which is of insulating material and is arranged so as to dissipate heat generated in the assembly; and a molding resin surrounding the electrical component. Heat, generated at electrical components in a circuit board assembly, is transferred and dispersed through the high-temperature dissipation material all over the assembly. Further, since the high-temperature dissipation resin is of an insulating material, it is unnecessary to consider a short-circuit problem in the assembly.