A functional molecular element exhibiting its function under the operation of an electrical field is provided. A compound is used in which a pendant molecule, formed by 4-pentyl-4′-cyanobiphenyl, exhibiting positive dielectric constant anisotropy or a dipole moment along the direction of the long axis of the molecule, is covalently bonded to an electrically conductive linear or film-shaped principal-axis molecule having a conjugated system. The pendant molecule is changed in its orientation on application of an electrical field to change the conformation to switch the electrical conductivity of the electrically conductive principal-axis molecule.