A semiconductor device includes a semiconductor chip, a core substrate, first and second insulating layers, and first and second wiring layers. Adhesiveness of the insulating layer to a metal is higher than adhesiveness of the core substrate to the metal. A through hole extends through the insulating layer in the thickness direction. A through via covers the hole wall surface of the through hole, extends in the thickness direction traversing the insulating layer, and electrically connects the first and second wiring layers.