A semiconductor device includes a wiring board having: plural stacked insulating layers; test pads and external connection pads which are disposed on a face of the plural stacked insulating layers located on the side opposite to that where another wiring board is connected; first wiring patterns which electrically connect internal connection pads with the test pads; and second wiring patterns which electrically connect semiconductor element mounting pads with the external connection pads. The external connection pads are placed on the inner side of the test pads.