A structure includes: a plurality of through holes that are provided to an insulating base and penetrate the insulating base in the thickness direction; conductive paths that are constituted of a conductive substance filling the plurality of through-holes; and insulators with which the plurality of through-holes are filled and are constituted of an insulating substance different from that of the insulating base. Both ends of the respective conductive paths are provided with protrusions that protrude from each surface of the insulating base in the thickness direction. Both ends of the insulators are flush with each surface of the insulating base in the thickness direction, protrude with respect to the surface in the thickness direction, or are recessed from the surface in the thickness direction.