TECHNOLOGY FOCUS - POLYMERS - Preferred Polymer Hybrid: The polysaccharide group polymer-inorganic polymer hybrid is a hybrid obtained by sol gel reaction of the polysaccharide group polymer and a metal alkoxide. The polysaccharide group polymer-inorganic polymer hybrid contains polysaccharide group polymer (A) and the inorganic polymer (B) in weight ratio (A/B) of 100/5-100/3. The ion electroconductive metallic salt is dissolved in the compound which dissolves ion electroconductive metallic salt such that the concentration of the obtained content is set to 0.1-5 M.Preferred Polysaccharide Polymer: The polysaccharide group polymer is a cellulose derivative of hydroxy alkyl cellulose.Preferred Inorganic Polymer: The inorganic polymer is a hydrolysis polycondensate of the metal alkoxide represented by formula M(OR)n.M = titanium or silicon atom;R = 1-4C alkyl;andn = valence of M.Preferred Process: Alternately, the catalyst is added to a solution of the polysaccharide group polymer, the metal alkoxide, the ion electroconductive metallic salt and the compound which dissolves ion electroconductive metallic salt. The metal alkoxide is hydrolyzed and polycondensed to form solution of gel solid electrolyte. The obtained solution is applied on a carrier to form a sheet. EXAMPLE - HPC-SL (TM) (hydroxy propyl cellulose) (in g) (2.25) was dissolved in methanol (42.75) at room temperature. PEO400 (TM) (polyethylene oxide (PEO) having molecular weight of 400) (7.5) was added. Lithium perchlorate was added in an amount of half the mol of PEO, and stirred to form homogeneous solution. Tetrabutoxy titanium (1.08) was added to the solution. 1N hydrochloric acid aqueous solution was dropped, and stirred at room temperature for 6 hours. The obtained solution was poured into a Petri dish made of polytetrafluoroethylene. The solvent was volatilized at room temperature for 4 days. The hybridization was performed by vacuum drying at 60 degrees C for 1 week. The dish was vacuum dried again at 100 degrees C for 1 week. The gel solid electrolyte sheet formed on the dish, was peeled from the dish. The gel solid electrolyte sheet had thickness of 0.38 mm. A stress distortion measurement was performed to the electrolyte sheet using a peel test machine. The film strength was 0.53.