A semiconductor device comprising: a semiconductor layer including a first electrode forming surface, a second electrode forming surface positioned opposite to the first electrode forming surface, and a side surface having a first edge as a boundary with the first electrode forming surface and a second edge as a boundary with the second electrode forming surface; a first electrode formed on the first electrode forming surface; a second electrode formed on the second electrode forming surface; and an insulating film continuously formed from the first electrode forming surface to the side surface so as to cover the first edge, wherein the side surface of the semiconductor layer is covered with the insulating film, wherein a side surface of the second electrode is exposed without being covered with the insulating film, wherein the semiconductor layer includes a semiconductor substrate constituting the second electrode forming surface and an epitaxial layer formed on the semiconductor substrate and constituting the first electrode forming surface, wherein at least a part of the first electrode comes into Schottky-contact with the epitaxial layer, and the second electrode comes into ohmic contact with the semiconductor substrate, wherein both the semiconductor substrate and the epitaxial layer have a tapered shape in which cross sections thereof are increased from the first electrode forming surface toward the second electrode forming surface, wherein the side surface of the semiconductor layer includes a first side surface of the semiconductor substrate and a second side surface of the epitaxial layer, and the first and second side surfaces are coplanar with each other over the full distance between the first edge and the second edge. a semiconductor layer including a first electrode forming surface, a second electrode forming surface positioned opposite to the first electrode forming surface, and a side surface having a first edge as a boundary with the first electrode forming surface and a second edge as a boundary with the second electrode forming surface; a first electrode formed on the first electrode forming surface; a second electrode formed on the second electrode forming surface; and an insulating film continuously formed from the first electrode forming surface to the side surface so as to cover the first edge, wherein the side surface of the semiconductor layer is covered with the insulating film, wherein a side surface of the second electrode is exposed without being covered with the insulating film, wherein the semiconductor layer includes a semiconductor substrate constituting the second electrode forming surface and an epitaxial layer formed on the semiconductor substrate and constituting the first electrode forming surface, wherein at least a part of the first electrode comes into Schottky-contact with the epitaxial layer, and the second electrode comes into ohmic contact with the semiconductor substrate, wherein both the semiconductor substrate and the epitaxial layer have a tapered shape in which cross sections thereof are increased from the first electrode forming surface toward the second electrode forming surface, wherein the side surface of the semiconductor layer includes a first side surface of the semiconductor substrate and a second side surface of the epitaxial layer, and the first and second side surfaces are coplanar with each other over the full distance between the first edge and the second edge.