The present invention aims to provide a PDP apparatus, where a sustain data pulse is applied to data electrodes during a sustain period, having high display quality,and capable of displaying a dark screen image vividly with high contrast without using an error diffusion method, as well as to provide a method of driving the PDP apparatus. In order to achieve the above object, the method of driving the PDP apparatus according to the present invention, during the sustain period, detects an average luminance of a screen image to be displayed, and sets a voltage waveform of a sustain data pulse to be applied to the data electrodes according to the detected average luminance, thereby modulating a luminance of the screen image.