It is an object of the present invention to provide a means for integrating an MEA and a pair of separators and regulate their positions without using parts that are specifically dedicated for position regulation use. More specifically, the present invention provides a polymer electrolyte fuel cell including a frame-integrated MEA, a separator having a channel for supplying and releasing a fuel gas, and a separator having a channel for supplying and releasing an oxidizer gas, and, in this fuel cell, the frame body of the frame-integrated MEA has a plurality of projections having a hook-shaped tip on both planes of the frame body and each separators has a plurality of stepped parts, and the projections on the frame body and the stepped parts on the pair of separators are integrated by fitting together with each other.