PURPOSE: To use an integrated vessel as the vessel for an electrolytic solution by integrating an outer cylinder member consisting of a soft photosetting resin material with a chemo-mechanical gel displacement structure consisting of a chemo-mechanical gel material.

CONSTITUTION: First/second base members 2a, 2b for composing a vessel with an outer cylinder 1 so that both ends of the outer cylinder. can be closed are installed on both ends of the outer cylinder 1 consisting of a soft photosetting resin material. A displacement structure 3 consisting of a chemo-mechanical gel material in which the end parts in the vessel are fixed respectively on the first/second base members 2a, 2b is provided. A first electrode 5a and a porous diaphragm 6 are respectively provided on the first/second base members 2a, 2b facing to a first clearance part 4a formed by the vessel and the displacement structure 3. A second electrode 5b is provided on the second base member 2b located at a position facing to the porous diaphragm 6 through the second clearance part 4b located between this porous diaphragm 6 and the second base member 2b. Therefore, the vessel for an electrolytic solution can be made.