NOVELTY - An ion-conductive polymer electrolyte comprises a polymer of polymerizable boron compound, a oxyalkylene-containing high-molecular compound, and glass-fiber nonwoven fabric. The mass ratio of polymer and high-molecular compound is 5/95-60/40. The nonwoven fabric contains an inorganic binder. The glass fiber has a diameter of 0.1-30 mu m. The fiber diameter of glass fiber having maximum fiber diameter is 3-100 times the fiber diameter of glass fiber having minimum fiber diameter.    USE - Ion-conductive polymer electrolyte is used for secondary batteries (claimed) and other electrochemical devices used for portable audio-video equipment, digital cameras, video cameras, portable audio players, portable liquid-crystal televisions, notebook computers, mobile telephones, and electronic organizers.    ADVANTAGE - The ion-conductive polymer electrolyte has excellent mechanical strength (even at a thickness of 100 mu m or less) and ionic conductivity, and low inflammability and volatile property. The electrolyte provides lightweight secondary batteries having low internal resistance. The usage amount of nonaqueous solvent is reduced.    DETAILED DESCRIPTION - An ion-conductive polymer electrolyte comprises a polymer of polymerizable boron compound of formula: Z1-(-OA1-)h-O-B(-O-(-A1O-)i-Z2)(-O-(-A1O-)j-Z3), a oxyalkylene-containing high-molecular compound of formula: R1O-(A2O)k-R2, and glass-fiber nonwoven fabric. The mass ratio of polymer and high-molecular compound is 5/95-60/40. The nonwoven fabric contains an inorganic binder. The glass fiber has a diameter of 0.1-30 mu m. The fiber diameter of glass fiber having maximum fiber diameter is 3-100 times the fiber diameter of glass fiber having minimum fiber diameter.    Z1-Z3=polymerizable functional group having an unsaturated double bond;    A1O,A2O=2-4C oxyalkylene;    h,i,j=average added mole number of oxyalkylene group, preferably 1-10;    R1,R2=1-10C hydrocarbyl or fluorine-containing hydrocarbyl;and    k=average added mole number of oxyalkylene group, preferably 4-20.    An INDEPENDENT CLAIM is included for secondary battery consisting of the ion-conductive polymer electrolyte interposed between a positive electrode (1) containing active material which occludes and discharges a cation, and a negative electrode (2) containing active material which occludes and discharges the cation discharged from the positive electrode, lithium atom, or lithium alloy, and moves the cation.    DESCRIPTION OF DRAWING(S) - The drawing shows a perspective view of the battery.    Positive electrode (1)    Negative electrode (2)    Positive electrode aluminum terminal (3)    Negative electrode nickel terminal (4)    Aluminum laminate film (5)