An electroconductive device includes a pair of oppositely disposed electrodes, a luminescence layer and an electroconductive layer disposed between the electrodes. The electroconductive layer includes a mixture of a plurality of organic compounds which are mutually structural isomers and include a major component and a minor component. The mixture contains the major and minor components in a (major component/minor component) ratio of 1/1 to 9/1. When the electroconductive layer is used as a carrier injection or transport layer, preferably an electron injection layer, a resultant electroluminescence (EL) device exhibits a high luminescence efficiency.