PURPOSE: To provide an electric field electron emitter capable of deficiency relief in such a manner so as to prevent a normal cathode electrode operation from being hindered due to a short-circuiting deficiency in the case where the short-circuiting deficiency is generated between the cathode electrodes and gate electrodes.

CONSTITUTION: A gate electrode containing a plurality of cathode electrodes is divided into a plurality of gate electrode elements 3. A gate branch line 6 constituted of a fusible resistor is inserted between the gate electrode element 3 and a gate main line 7. The gate branch line 6 is broken due to an exceesive current flowing upon short-circuiting between the cathode electrode 5 and gate electrode element 3 in the same manner as a fuse, thus separating the gate electrode element 3 where a short-circuiting deficiency is generated by itself. Consequently, the cathode electrode 3 in a normal operation can be operated without difficulty.