<p>An artificial neural function circuit includes an organic thin film element (1 to 9) the resistance state of which changes in dependence on an electrical signal inputted thereto and exhibits information processing function similar to that of the nervous system. The organic thin film element has such physical properties that the changed resistance state is held as it is at least for a predetermined time period even after removal of the electric input signal and that the direction in which the resistance is increased or decreased depends on the polarity of the electric input signal. As an example of such organic thin film, a lead phthalocyanine thin film is employed. <IMAGE></p>