The present invention provides a semiconductor device capable of being miniaturized and preventing reduction of mountability to a wiring substrate. The semiconductor device includes a conductive support having a support surface and a mounting surface facing opposite sides in a thickness direction z, and an end surface intersecting with the mounting surface and facing outside; a semiconductor element having an element back surface facing the support surface and an electrode formed on the element back surface, in which the electrode is connected to the support surface; and an external terminal conducted to the mounting surface and exposed to the outside; wherein the external terminal includes a Ni layer having P and an Au layer, and respectively connected to and laminated with at least one portion of each of the mounting surface and the end surface.