Abstract: The present invention provides a storage device including a storage element, a circuit element, and write control means. The storage element has a characteristic exhibiting a resistance changing from a large value to a small value due to application of an electrical signal at least equal to a first threshold signal but changing from a small value to a large value due to application of an electrical signal at least equal to a second threshold signal. The circuit element is connected in series to the storage element. The write control means is configured to carry out a first write operation, detect a resistance by the storage element after an n-th write operation, where n?1, compare the detected resistance with the set value, and carry out a (n+1)-th write operation.