A flat display apparatus is disclosed which includes a grid interposed between and spaced apart from control electrodes and an electron source. The grid which includes holes has a higher potential applied than the one applied to a cathode so as to enable electrons to pass through the holes. An additional grid may be interposed between and spaced apart from the grid and the control electrodes. Alternatively, a rear electrode is located between adjacent porous cover electrodes to connect them, and a second rear electrode is located near the rear electrode and has a lower potential applied than the one applied to the cover electrodes.