A laminated electronic device comprises two or more wiring layers including a first wiring layer and a second wiring layer, an insulating layer interposed between the first wiring layer and second wiring layer, and a through conductor extending through the insulating layer for electrically connecting a first conductor disposed on the first wiring layer to a second conductor disposed on the second wiring layer. The through conductor includes divergent sections at both ends, which have a diameter gradually increased toward the first conductor or second conductor.