The present invention provides a gas diffusion electrode capable of sufficiently preventing not only degradation of MEA during storage but also degradation of initial characteristics and durability during the time period from production to initial use, and a polymer electrolyte fuel cell including the gas diffusion electrode. The gas diffusion electrode includes a catalyst layer in which A1 representing a total mass of organic substance comprising alcohol, a partial oxide of the alcohol, a product of intramolecular dehydrogenation reaction of the alcohol, a product of intermolecular condensation reaction of the alcohol, a product of intermolecular condensation reaction between the alcohol and the partial oxide and a product of intermolecular condensation reaction of the partial oxide, E1 representing a total mass of carbon powder and G1 representing a total mass of cation exchange resin are controlled to satisfy {100×A1/(E1+G1)}≦0.05.