An additional dielectric layer (11A) is formed on a backside of a dielectric layer (11) to protrude to the inside of a discharge space (S) and extend along an edge of a discharge cell C in parallel to the row direction. Row electrodes (X, Y) respectively have bus electrodes (Xb, Yb) extending along the edge of the discharge cells (C) in the row direction, and transparent electrodes (Xa, Ya) paired with each other in each discharge cell C. An overlap portion (m) of a proximal end (Xa3, Ya3) of each transparent electrode (Xa, Ya) connected to the bus electrode (Xb, Yb), which overlaps the additional dielectric layer (11A), is designed to be smaller in width than that of a linking portion (Xa2, Ya2) between the overlapping portion (m) and a distal end of the transparent electrode.