GAS CHANNEL FORMING MEMBER FOR FUEL CELLS, AND FUEL CELL

A gas channel forming member (31) is located between a separator (23) and a membrane electrode assembly (15), which has a polymer electrolyte membrane held between a pair of electrode catalyst layers. The gas channel forming member (31) includes gas channels (32), which are arranged in parallel with each other on a surface that faces the membrane electrode assembly (15), water channels (33), which are formed on a surface that faces the separator (23), and inner communication passages (36). The water channels (33) are each located between adjacent two of the gas channels (32). The inner communication passages (36) communicate the gas channels (32) and the water channels (33) with each other. Oxidant gas flows through the gas channels (32), and generated water (W) is discharged through the water channels (33). Each water channel (33) is formed such that the flow cross-sectional area in an outlet section (34) including an outlet opening (33a) is larger than the cross-sectional area of an upstream section (35), which is upstream of and adjacent to the outlet section (34) in the flow direction of the oxidant gas.