In a panel unit 10, a discharge gas is filled into a discharge space 13. A protective layer 114 is provided in a partial region (a front panel 11 side) facing the inner space 13, and a phosphor layer 124 is provided in a counter region (a back panel 12 side) which holds the discharge space 13. The discharge gas is set at a total pressure of not less than 1.50×104 [Pa] and not more than 6.66×104 [Pa], and comprises an Xe gas as a first gas component and an Ar gas as a second gas component and is free from an Ne gas, provided that the Ne gas may be contained in the discharge gas at a partial pressure ratio of not more than 0.5[%] based on the total pressure.