PURPOSE: To improve the conservation performance by constituting a separator from cellophane and polyamide or polyvinylchloride in the three-dimensional continuous porous structure having the increasing diameter of the hole from a thick layer on one side to a porous layer on the other side.

CONSTITUTION: A separator 4 interposed between a positive electrode 1 and an electrolyte absorbing substance 3 which contacts with a negative electrode 2 and is made of vinylon-rayon mixed paper and nonwoven fabric etc. is constituted of cellophane 400 and continuous porous polyamide or polyvinylchloride in three dimensional structure, and said cellophane 400 is arranged so as to be placed on the electrolyte absorbing substance 3 side, namely so that the porous film 40 described in the above contacts with the positive electrode 1. Therefore, the silver oxide powder having a relatively large diameter in minute particle form are checked by a porous layer 40B having a large diameter of the hole on the entry side, and the silver oxide powder having the more minute diameter are checked by a thick layer 40A on the exit side, so mesh-clogging can be prevented, and the sufficient separating faculty with the improved ion transmissivity can be developed.