A plasma display panel; a scan electrode drive circuit for generating a gently decreasing downward inclined waveform voltage in an initializing period, a gently increasing first inclined waveform voltage, and a second inclined waveform voltage having a steeper gradient than the first inclined waveform voltage and decreasing immediately after the increasing waveform voltage reaches a predetermined potential in the last part of the sustain period. The lowest voltage in the downward inclined waveform voltage is switched at a first voltage, a second voltage higher than the first voltage and a third voltage higher than the second voltage to generate a downward inclined waveform voltage. The lowest voltage is switched according to the detected temperature to generate the downward inclined waveform voltage.