Bus electrodes Xa, Ya, transparent electrodes Xb, Yb, and column electrode protrusions Db are formed on a front glass substrate 1. A leading end of the transparent electrode Xb (Yb) is opposite another leading end of the transparent electrode Yb (Xb), connected to the bus electrode Ya (Xa) adjacent thereto, with a first discharge gap g1 interposed in between. One or other of the transparent electrodes Yb and Xb is opposite the column electrode protrusion Db with a second discharge gap g2 in between. A column electrode body Da is separated from the bus electrodes Xa and Ya through the first dielectric layer 2. A phosphor layer 6 is provided on a back glass substrate 4.