To provide a structure quickly suppressing a differential pressure between an anode and a cathode in a solid polymerelectrolyte fuel cell using a solid polyelectrolyte membrane as an electrolyte layer.

A membrane electrode junction body 1 formed by holding an ion exchange membrane between electrodes is held between two gas separators to compose the fuel cell A. A gas pressure suppressing chamber 2 is provided in a gas inlet side of the fuel cell A, differential pressure buffering chambers 2a and 2b are formed by dividing the interior of the gas pressure suppressing chamber 2 into two chambers by a movable partition 3 comprising elastic material, fuel as is supplied to the anode 4a of the fuel cell A via the differential pressure buffering chamber 2a, and oxidizer gas is supplied to the cathode 5a of the fuel cell A via the differential pressure buffering chamber 2b. When a differential pressure occurs between an anode line 4 and a cathode line 5, the movable partition 3 is pushed from a higher internal pressure side to a lower internal pressure side, volumes of the differential pressure buffering chambers 2a and 2b are changed, and the differential pressure is suppressed.