To provide an electron-emitting element which offers a large emission current without inviting an increase in the size of the electron-emitting element and can be manufactured easily, an electron source using the electron-emitting element, and an image display device using the electron source which offers fine image quality and high definition.

The electron-emitting element includes a first cathode, a second cathode, a third cathode, an insulating layer, a gate electrode, and an electron-emitting material. The gate electrode, the insulating layer, and the second cathode have respective openings through which the gate electrode, insulating layer, and second cathode communicate with each other. The electron-emitting material is formed on the first cathode, where at least part of the electron-emitting material is exposed in the opening. The third cathode is so formed in the opening of the second cathode as to increase the length of the outline of an exposure area of the electron-emitting material, and is connected electrically to the first cathode.