In a barrier-rib forming apparatus for forming barrier ribs on a substrate by discharging rib material from a discharge part, an oscillating mechanism for oscillating the discharge part in a direction perpendicular to a traveling direction of a stage which supports the substrate is provided to form barrier ribs of waveform on the substrate. The travel of the stage is performed twice, and at the second travel of the stage, each of barrier ribs is formed between adjacent ones of the already-formed barrier ribs. The barrier rib formed at the first travel of the stage and that formed at the second travel of the stage are disposed symmetrically to each other with respect to an axis parallel to the travel direction of the stage. With this formation of barrier ribs, it is possible to manufacture a panel which allows improvement in luminance of a plasma display.