Method for restoring performance of polymer electrolyte fuel cell

The present invention relates to a method for restoring the performance of a polymer electrolyte fuel cell by: operating said polymer electrolyte fuel cell for a predetermined time either in an operation mode at a current of not less than 1.5 times as high as that in a normal operation, or in an operation mode at a current giving an output voltage per unit cell of not more than 0.2 V.