A separator includes a first fuel gas supply unit, a second fuel gas supply unit, first sandwiching sections, second sandwiching sections, a first case unit and a second case unit. The first and second sandwiching sections are connected to the first fuel gas supply unit and the second fuel gas supply unit, respectively, through first bridges. The first case unit and the second case unit are connected to the first sandwiching sections and the second sandwiching sections through second bridges. A first surface pressure F1 generated near a fuel gas supply passage, a second surface pressure F2 generated near an oxygen-containing gas supply passage, and a third surface pressure F3 generated near electrolyte electrode assemblies have different values.