In a polymer electrolyte fuel cell in which a cathode diffusion layer, a
cathode electrode catalyst layer, a polymer electrolyte membrane, an
anode electrode catalyst layer, and an anode diffusion layer are
laminated in this order, electron conductivity of the cathode electrode
catalyst layer at a portion on the side of the cathode diffusion layer is
higher than at a portion on the side of the polymer electrolyte membrane
and electron conductivity of the cathode electrode catalyst layer at the
portion on the side of the polymer electrolyte membrane is lower than at
the portion on the side of the cathode diffusion layer, and furthermore,
electron conductivity of the anode electrode catalyst layer at a portion
on the side of the anode diffusion layer is higher than at a portion on
the side of the polymer electrolyte membrane and electron conductivity of
the anode electrode catalyst layer at the portion on the side of the
polymer electrolyte membrane is lower than at the portion on the side of
the anode diffusion layer.