An apparatus for controlling the drive power of a plasma display panel in an driving apparatus of the plasma display panel. The apparatus preestimates a load ratio of an input video signal on a frame-by-frame basis, controls a number of display-discharge pulses in a corresponding frame to be inversely proportional to the preestimated load ratio, measures correlation of each frame with a preceding frame, controls the output timing of a discharge number controller according to the correlation and regulates a rate of change of the number of display-discharge pulses in a frame. The number of display discharge pulses in a frame is regulated to change more rapidly where the correlation is low and than where the correlation is high.