A bypass plate and an intermediate plate are interposed between a stack body and a negative electrode terminal of a fuel cell stack. An oxygen-containing gas passage extends through the bypass plate and the stack body. The intermediate plate has a small opening. The opening has a cross sectional area smaller than a cross sectional area of the oxygen-containing gas supply passage. The opening is formed by an extension extending into the oxygen-containing gas supply passage. The extension removes water in the oxygen-containing gas, and discharges the water into a bypass flow passage.