An electrical interconnection assembly which prevents a slack of insulated wire pieces interconnecting wire receiving terminals and is high in reliability in electric connection between them and suitable for high density wiring. The assembly comprises an insulating support body, a plurality of wire receiving terminals mounted on the insulating support body and each having a wire receiving slot formed at an end portion thereof, each of the wire receiving terminals having a terminal portion at the other end thereof, an insulated wire selectively received in the slots of the wire receiving terminals and cut into a plurality of wire pieces in such a manner as to form a predetermined wiring pattern, and a plurality of wire holding bosses provided on the insulating support body for holding intermediate portions of the wire pieces extending between the wire receiving terminals to retain the insulated wire in the predetermined wiring pattern. Also a process of and an apparatus for manufacturing such electrical interconnection assembly and a wire laying jig for use with such process and apparatus are disclosed.