Semiconductor device includes semiconductor substrate, through hole having first opening and second opening, and including an expansion portion so that an opening area of first opening is greater than an opening area of lowermost portion of expansion portion, first insulating layer, and having an opening which communicates with through hole and has an area smaller than opening area of first opening, first wiring layer provided on first insulating layer, second insulating layer provided on expansion portion of through hole, and to cover first opening and an inner wall surface of through hole, second insulating layer having an opening communicating with opening of first insulating layer so as to expose first wiring layer through opening of first insulating layer, and second wiring layer provided on second insulating layer to extend from inside of through hole, and being connected to first wiring layer via openings of first and second insulating layers.