A surface on the fuel electrode side of a lower portion of a separator in a fuel cell stack is made to have water repellency, so that water accumulated in a fuel gas flow path can be appropriately discharged, and thus so that reduction in fuel cell performance and deterioration of the fuel electrode can be surely prevented. For that purpose, in a fuel cell device, a fuel cell having an electrolyte layer interposed between the fuel electrode and an oxygen electrode includes a cell module laminated so as to interpose a separator formed with the fuel gas flow path along the fuel electrode, and a fuel gas flows substantially perpendicularly to the direction of gravity in the fuel gas flow path. The separator is provided with a water-repellent surface on the fuel electrode side of a lower portion thereof.