A display electrode and a dielectric layer are formed on the convex side of a front glass substrate that is convexly curved in profile, whereas address electrodes, a dielectric layer, partition walls and phosphor layers are formed on the convex side of a back glass substrate 15 that convexly curved in profile. Further, a sealing layer containing granular substances in a sealing material is formed in the peripheral portion of the back glass substrate. A front panel and a back panel are stacked so that the panel component parts of the front panel are set opposite to the panel component parts of the back panel. Then the peripheral portions of the panels are pressed against each other into a flat substrate plate as shown by arrows and heated up.