Flow guides forming an inlet channel are formed on a surface of a metal separator of a fuel cell. The flow guides overlap a section of an outer seal provided on the other surface of the metal separator. When a load is applied to the flow guides and the overlapping section in a stacking direction of the fuel cell, the flow guides and the overlapping section are deformed substantially equally in the stacking direction to the same extent. The line pressure of the flow guides and the line pressure of the overlapping section are substantially the same. The seal length L1 of the flow guides and the seal length L2 of the overlapping section are substantially the same.