A PDP having an opposing electrode structure including first and second substrates facing each other. A space between the first and second substrates is divided into discharge cells. Address electrodes extend in a first direction between the first and second substrates, and first and second electrodes extend in a second direction intersecting the first direction while being spaced apart from the address electrodes. At least one of the address electrodes or the first and second electrodes has a protruding portion that protrudes toward the center of each discharge cell. The protruding portions help reduce the discharge gap which in turn reduces the discharge firing voltage. Expansion portions formed as parts of the first and second electrodes increase the discharge gap used by the sustain discharge and lead to an improved luminescence efficiency.