Memristor and neural network using same

Provided is a memristor that can be manufactured at a low temperature, and does not include metals of which resources might be depleted. This memristor includes a first electrode, a second electrode, and a memristor layer of an oxide having elements of Ga, Sn, and oxygen, disposed between the first electrode and the second electrode. When voltage is applied to the first electrode with respect to the second electrode, the voltage being positive or negative, a current flows; when voltage of a data-set voltage value is applied, a state is transitioned from a high-resistance state to a low-resistance state; and when voltage of a data-reset voltage value that is of an opposite sign to that of the data-set voltage value is applied, the state is transitioned from a low-resistance state to a high-resistance state.