A semiconductor device includes: a semiconductor substrate having an active surface and a back surface; an integrated circuit formed on the active surface; a feedthrough electrode penetrating the semiconductor substrate, and projecting from the active surface and the back surface; a first resin layer formed on the active surface, having a thickness greater than a height of a portion of the feedthrough electrode that projects from the active surface, and having an opening portion for exposing at least a portion of the feedthrough electrode; a wiring layer which is formed on the first resin layer, and which is connected to the feedthrough electrode through the opening portion; and an external connecting terminal connected to the wiring layer.