Emitter contact holes formed under emitter electrodes in a first layer and emitter through holes formed thereon are arranged so as not to overlap each other, and, for each emitter electrode, the multiple emitter contact holes and the multiple emitter through holes are provided so as to be separated from each other. Thereby, the top surface of an emitter electrode in a second layer is influenced by at most only a level difference of each emitter through hole formed in an insulating film having a larger thickness, and thus the flatness of the top surface of the emitter electrode in the second layer is improved. Accordingly, fixation failure of a metal plate can be avoided.