In an electron-emitting device having an electron-emitting member containing carbon as a main component, and an extraction electrode arranged near the electron-emitting member, electrons can be emitted by substantially only a region of the electron-emitting member close to the extraction electrode. Brightness nonuniformity and abnormal lights-on errors are reduced in an image forming apparatus in which the electron-emitting devices are constituted into an electron. The electron-emitting threshold field of the electron-emitting member is set low at a portion close to the extraction electrode and high at a portion apart from the extraction electrode.