To provide a thermion emission device which includes carbon nano tubes specifically.

The thermion emission device includes a base plate, an insulative base plate, and at least one lattice formed on the insulative base plate. Each of the lattices includes four electrode leading wires arranged around each lattice and a thermion emission unit. The thermion emission unit includes two electrode and thermion emission elements. The two electrodes are connected electrically with thermion emission elements. Corresponding to the lattice, there are formed a plurality of grooves on the insulative base plate.