A fuel cell includes a membrane electrode assembly and a metal separator. The metal separator is stacked with the membrane electrode assembly. A reactant gas passage is provided between the membrane electrode assembly and the metal separator to supply a reactant gas along an electrode surface. The metal separator includes a reactant gas communication hole to communicate with the reactant gas passage. The metal separator further includes a plurality of groove groups each having a plurality of grooves press-formed to allow the reactant gas communication hole to communicate with the reactant gas passage. The grooves adjacent to each other are spaced apart by a first distance. The groove groups adjacent to each other are spaced apart by a second distance larger than the first distance.