An electron-emitting device having an electron-emitting region between electrodes on a substrate where the electron-emitting region contains fine particles dispersed therein at an areal occupation ratio of the fine particles ranging from 20% to 75% of the electron-emitting region is disclosed. The other electron-emitting device where the electron-emitting region contains fine particles being arranged at gaps of from 5 Å to 100 Å and having average particle diameter of from 5 Å to 1000 Å is also disclosed. Electron beam-generating apparatus and image-forming apparatus comprise one of the electron-emitting regions and a modulation means for modulating the electron beams emitted from the electron-emitting devices in accordance with information signals.