The forming voltage of a variable resistance device used in a non-volatile memory and the like is decreased, and repetition characteristics are improved. In an element structure in which a metal oxide film is sandwiched between a lower electrode and an upper electrode, an island-shaped/particulate region of amorphous aluminum oxide or aluminum oxycarbide is formed on the metal oxide film. Because an oxide deficiency, serving as the nucleus of a filament for implementing an on/off operation of the variable resistance device, is formed from the beginning under the island-shaped or particulate aluminum oxide or the like, the conventional creation of an oxide deficiency by high-voltage application in the initial period of forming can be eliminated. Such a region can be fabricated using a small number of cycles of an ALD process.