TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Solution: The electrolytic solution contains 0.1-3 mol/l of electrolyte. The composite gel electrolyte is impregnated in the porous separator.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Solvent: The non-aqueous solvent is carbonate ester, lactone, sulfolane, N-methyl pyrrolidone and/or trimethyl phosphate.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Solution: The electrolytic solution contains 0.1-3 mol/l of electrolyte. The composite gel electrolyte is impregnated in the porous separator.    TECHNOLOGY FOCUS - POLYMERS - Preferred Properties: The polysiloxane (B1) has etherification rate of 10% or more, and terminal hydroxyl group is blocked, such that non-block hydroxyl group value is 25 or less. Preferred Polymers: The polymer (B2) is polyacrylonitrile, polyethyleneglycol or polymethyl methacrylate. The polymer (B2) has ethylene unit and/or propylene unit, and unsaturated carboxylic acid unit in which carboxyl group is esterified by polyalkylene glycol in which one terminal hydroxyl group is protected. Preferred Matrix: The matrix (A) comprises a cross-linkable monomer having two or more of reactive functional groups chosen from vinyl, epoxy, amino, amide, imide, hydroxyl, methylol, carboxyl and isocyanate. Preferred Composition: The gel electrolyte contains non-bridge polymer (in weight parts) (1), non-aqueous electrolytic solution (3 or more) and cross-linked polymer matrix (0.1-3). The polymer (B) contains polysiloxane (B1) (1-300) with respect to polymer (B2) (100). EXAMPLE - Alkylene glycol modified copolymer (10 g) having unreacted acrylic acid content of 3 wt.% and unreacted terminal methylated polyethylene glycol content of 3 wt.% was dissolved in electrolytic solution (90 g) containing lithium bromo tetrafluoride (1 mol/l), ethylene carbonate and propylene carbonate. The obtained reaction mixture solution was gelatinized, to obtain a composite gel electrolyte. Electrolyte had excellent impregnating ability and ionic conductivity of 2.8 mS/cm.