PURPOSE: To maintain close contacting property between an electrode plate and an electrolytic plate and eliminate shearing deformation of the electrolytic plate by allowing a holder to rise up from a separator plate in the form of a cantilever, and thereby providing it with resilience.

CONSTITUTION: A separator 25 is provided with a holder 29 and a separator plate 27 to partition between unitary cells consisting of an electrolytic plate 3, a positive and a negative electrolytic plates 5, 7, which are piled up one over another. The holder 29 is jointed to the two side edges of the separator plate 27 by means of brazing, etc., and composed of springs 29, which are bent and rise as cantilever on the upper and lower sides of separator plate 27, and a flat receptacle 29b formed at the outer end of these springs. When the pressing force of a gas channel is sunk by decrease in the thickness of the electrode plates 5, 7, the holder 29 of the separator 25 is deflected resiliently by compressive lead to cause decrease in the height until the pressing force is restored. This maintains close contacting property between the electrode plates 5, 7 and the electrolytic plate 3, and no excessive deformation is applied to the electrolytic plate 3.