Provided is a field emission device. The field emission device includes an insulated cathode substrate facing an anode substrate, a plurality of cathodes arranged on the cathode substrate and separated from each other, and an emitter formed on each of the cathodes. In order to prevent accumulation of charges on an exposed area of the cathode substrate between the cathodes due to electrons discharged from the emitter, the distance between the cathodes is equal to or smaller than a first threshold value, and the distance from the emitter to the end of the cathode is equal to or greater than a second threshold value. Accordingly, in the field emission device in which a plurality of cathodes are separated from each other on the same plane, it is possible to prevent abnormal field emission and arc generation due to accumulated charges between the cathodes, thereby performing stable operation.