Embodiments of the present invention offer an improved PDP that offers a lowered discharge initiation voltage as well as improved efficiency of discharge. The PDP may satisfy the equation 180.ltoreq.(A+B)+P.times.0.1.ltoreq.240 in which A is a distance between opposite recessed portion of a pair of a first electrode and a second electrode; it is a distance between opposite projection portions of the pair of the first electrode and the second electrode, and P is a gas pressure of a discharge gas contained in the discharge space. In another embodiment a gas pressure of a gas trapped in a discharge space (e.g., "cell" or "discharge cell") may be over 450 Torr. Additionally, each opposing end of the first electrode and the second electrode may include a recessed portion and a projection portion such that a gap interposed between the opposing end portions varies in width.