as the first and third short erase pulses 7 and 8 these potentials can be different from each other in similar fashion in spite of the foregoing description about a case in which the sustaining pulse 9 is the same in potential as the second short erase pulse 10 the respective potentials can be different from each other as shown in fig1 the first short erase pulse 46 is lower in potential than the sustaining pulse 39 the second short erase pulse 47 lower in potential than the first short erase pulse 46 and the third short erase pulse 48 lower in potential than the second short erase pulse 47 this progressive reduction in the potential of the short erase pulses permits an even more effective erasure the present embodiment is concerned with the erasure of main discharge performed between the line electrodes of the face plate 15 the discharge performed by the trigger t electrode 23 and the address a electrode 25 on the back plate 22 can also be erased without fail by applying similar short erase pulses fig1 shows discharge erasing waveforms 61 62 applied to the address a electrode 25 and the trigger t electrode 23 on the back plate 22 for accurate discharge erasure to be performed also.