At a primary power-supply board 40, a V.sub.sus power supply and a V.sub.add power supply of prescribed voltages are derived and outputted to a plasma display panel 11. Secondary power supplies V.sub.sub1, V.sub.sub2, and V.sub.sub3 are derived from prescribed voltage levels of a transformer 42 for deriving V.sub.sus and V.sub.add power supplies at the primary power-supply board 40. The secondary power supplies V.sub.sub1, V.sub.sub2, and V.sub.sub3 are outputted to a secondary power-supply board 20 which is a board different from the primary power-supply board 40. V.sub.set, V.sub.e, and V.sub.scan power supplies which can be used by the plasma display panel 11 are derived by regulating the secondary power supplies V.sub.sub1, V.sub.sub2, and V.sub.sub3. Thus, since the primary power-supply board 40 and the secondary power-supply board 20 are provided separately, the secondary power-supply board 20 alone can be replaced to cope with the changes of the plasma display panel 11.