The present specification discloses a polymer electrolyte fuel cell comprising a stack containing a plurality of unit cells laminated, compressed and retained via a retaining plate, the unit cell comprising a pair of electrodes sandwiching a polymer electrolyte membrane therebetween and a conductive separator plates having a gas supply channel on at least one surface thereof and sandwiching the electrodes therebetween, wherein the retaining plate forms a gap between the unit cells. According to the fuel cell of the present invention, it is possible to readily remove a defective unit cell from the stack and replace the same.