A unit cell of a fuel cell includes a membrane electrode assembly and an anode side metal separator and a cathode side metal separator sandwiching the membrane electrode assembly. A plurality of first supply holes and a plurality of second supply holes extend through a channel unit of the anode side metal separator, and the channel unit connects a fuel gas supply passage and a fuel gas flow field. A fuel gas from the fuel gas supply passage flows into the first supply holes, and flows through an inlet connection channel. The fuel gas flows into the second supply holes connected to an end of the inlet connection channel. The fuel gas flows toward the side of the membrane electrode assembly, and then, the fuel gas is supplied to an anode.