; (0) exposing selectively the photosensitive composition layer to light so as to form ion-exchange groups in the light exposed portion; and (0) forming the conductive portion by bonding a metal ion or metal to the ion-exchange group formed in the light exposed portion by the exposing. According to a fourth aspect of the present invention, there is provided a method of manufacturing a composite member in which a conductive portion is selectively formed in an insulating body, comprising: (0) forming a photosensitive composition layer within or on the surface of said insulating body, said photosensitive composition containing a compound having an ion-exchange group; (0) exposing selectively the photosensitive composition layer to light so as to cause ion-exchange groups in the light exposed portion to disappear and to cause the ion-exchange groups to remain in the unexposed portion; and (0) forming the conductive portion by bonding a metal ion or metal to the ion-exchange group remaining in the unexposed portion after the 