A polymer electrolyte fuel cell of the present invention includes a membrane-electrode assembly (5) and separators (6A and 6B). Each of the electrodes (4A and 4B) includes a catalyst layer (2A, 2B) and a gas diffusion layer (3A, 3B). One main surface of the catalyst layer contacts the polymer electrolyte membrane (1). The separator (6A) includes a peripheral portion (16A) and a portion (26A) other than the peripheral portion. The peripheral portion (16A) of the separator (6A) is formed in an annular shape when viewed from a thickness direction of the separator (6A) and is a region including a portion located on an inner side of the outer periphery of the separator (6A). The separator (6A) is configured such that a porosity of the peripheral portion (16A) is higher than that of the portion (26A) other than the peripheral portion.