Abstract: A horizontal type electron-emitting device structure and process of making, wherein the device includes a low-potential electrode and a high-potential electrode which are formed on a substrate, and an electron-emitting part placed between the electrodes. Above the substrate is an anode. A secondary-electron emitting material is arranged on the top of a region from the electron-emitting part to the high-potential electrode, so that secondary electrons are efficiently emitted to the anode, thereby to contribute to efficient electron emission. An auxiliary electrode may be formed, with a high-resistance or insulating layer interposed, on the substrate in the vicinity of the high-potential electrode. A voltage higher than that of the high-potential electrode is then applied to the auxiliary electrode, so that electrons emitted from the electron-emitting part are attracted to the auxiliary electrode.