The present invention provides an electron emitting device including electrodes disposed with a space therebetween on a surface of a substrate, a carbon film disposed between the electrodes and connected to one of the electrodes, and a gap disposed between the carbon film and the other electrode. In the gap, the distance between the edge of the carbon film connected to one of the electrode and the edge of the other electrode at an upper position apart from the surface of the substrate is smaller than that at the surface of the substrate. The present invention also provides an electron source and an image display device each including the electron emitting device.