An electron-emitting device having little dispersion of its electron emission characteristic and a suppressed "fluctuation" of its electron emission quantity is provided. The electron-emitting device includes a substrate equipped with a first portion containing silicon oxide and a second portion arranged abreast of the first portion and having a higher heat conductance, and an electroconductive film including a gap therein, the electroconductive film arranged on the substrate, wherein the first and the second portions having a resistance higher than that of the electroconductive film, and the gap is arranged on the first portion.