An electron beam apparatus is provided having an electron emitting device which has a simple configuration, exhibits high electron emission efficiency, operates stably, and in which emitted electrons are effectively converged. The electron beam apparatus includes: an insulator having a notch on its surface; a gate positioned on the surface of the insulator; at least one cathode having a protruding portion protruding from an edge of the notch toward the gate, and positioned on the surface of the insulator so that the protruding portion is opposed to the gate; and an anode arranged to be opposed to the protruding portion via the gate, wherein the gate is formed on the surface of the insulator so that at least a part of a region opposed to the cathode is projected outward and recessed portions are provided in which ends of the gate are recessed and interpose the projected region.