To provide a field emission electron source having high reliability while improving emission characteristics, and to provide a light-emitting device using the field emission electron source.

In the light-emitting device 20, the field emission electron source 10 having a lower electrode 2, a surface electrode 4 opposed to the lower electrode 2, and an electron passing-through layer 3 intervened between the lower electrode 2 and the surface electrode 4 for passing electrons, wherein electrons passing through the electron passing-through layer 3 are emitted through the surface electrode 4 formed by changing its film thickness continuously or gradually, is arranged to face a collector electrode 23 and a phosphor layer for emitting fluorescence by excitation light emitted in a light-emitting process of excited Xe gas, in an airtight container 21 wherein the Xe gas is enclosed and at least partly formed of a light-transmitting material. The light-emitting device 20 controls voltage applied to the field emission electron source 10 and voltage between the collector electrode 23 and the field emission electron source 10 by a control device 25.