A fuel cell is provided with: a membrane electrode assembly (MEA); and a cathode-side separator assembled to the MEA, the cathode-side separator including first passages on a first surface of the cathode-side separator on a side closer to the MEA, and second passages on a second surface of the cathode-side separator on an opposite side, the first and second passages allowing oxidant gas to flow through the first and second passages, respectively. The first passages include first recessed portions on the first surface so as to extend from one end of the cathode-side separator to the other end,the second passages include second recessed portions on the second surface so as to extend from the one end to the other end and to be arranged alternately with the first recessed portions, and a penetration hole on a bottom face of the second recessed portion penetrating through the cathode-side separator.