In one example embodiment, a molecular element is configured by bridging a gap between a source electrode and a drain electrode by a functional molecule. The functional molecule arises from covalent linkage of a side chain composed of a pendant molecule that has dielectric constant anisotropy and/or dipole moments and in which orientation change occurs due to an electric field to a main chain composed of a conjugated molecule in which structural change occurs due to the orientation change of the pendant molecule and an electrical characteristic changes. The molecular element is made to work as a diode, a transistor, or a memory by an electric field applied to the pendant molecule of the functional molecule by gate electrodes.