Abstract: A semiconductor device includes a semiconductor substrate; an anode electrode, formed on a surface on one side of the semiconductor substrate; a cathode electrode, formed on a surface on the other side of the semiconductor substrate; a P layer, formed on the anode electrode side in the semiconductor substrate; and an N layer, formed on the cathode electrode side in the semiconductor substrate and on the other side of the P layer. The cathode electrode and the N layer are Schottky functioned, the cathode electrode is a metal having work function ranging from 4.2 to 4.3, and the carrier concentration of the N layer ranges from 1×e12 to 1×e18/cm3.