An AlN single crystal Schottky barrier diode including: an AlN single crystal substrate having a defect density of 106 cm−2 or less and a thickness of 300 μm or more; a first electrode formed on one surface of the AlN single crystal substrate; and a second electrode formed on one surface of the AlN single crystal substrate while being spaced apart from the first electrode, the AlN single crystal Schottky barrier diode being provided with: a rectifying property such that an on-off ratio at the time of applying 10 V and −40 V is at least 103 even at a high temperature of 573 K; a high voltage resistance such that a voltage can be applied at least within a range of −40 V to 10 V; and a low on-resistance characteristic such that a current begins to flow at no greater than 5 V.