NOVELTY - Polymer electrolyte fuel cell includes a first group of oxidizing gas flow passages flowing, from an entrance towards a turning point, has longer length than a second group of oxidizing gas flow passages, from the turning point towards an exit. A downstream of the flow passages of the first group is located near an upper stream of the flow passages of the second group. The flow passages of the two groups are joined to one another on the plane of a separator.    USE - For generating electric power in an electric appliance.    ADVANTAGE - The fuel cell is capable of generating electric power at stable voltage and without disposing a humidifier to an exterior of the fuel cell. If water produced in the fuel cell can be circulated or recycled in the fuel cell, spaces for the auxiliary equipments can be omitted or minimized.    DETAILED DESCRIPTION - Polymer electrolyte fuel cell comprises first separator for oxidizing gas, a second separator for fuel gas, and a membrane/electrode assembly sandwiched between the separators. A first group of oxidizing gas flow passages flowing, from an entrance towards a turning point, has longer length than a second group of oxidizing gas flow passages, from the turning point towards an exit. It is formed on a plane of the first separator. A downstream of the flow passages of the first group is located near an upper stream of the flow passages of the second. The flow passages of the first and second groups are joined to one another on the plane of the first separator.    An INDEPENDENT CLAIM is included for a separator for separating fuel gas from oxidizing gas comprising a hole (104, 112) for introducing the oxidizing gas. An exit manifold discharges the oxidizing gas. Flow passages communicate between the holes and the exit manifold. Two points between a pair of joining flow passages for oxidizing gas include portions where oxidizing gas with different humidity flows.    DESCRIPTION OF DRAWING(S) - The figure is an enlarged plane view of oxidizing gas flow passages.    Hole (104, 112)    Rib (113)