NOVELTY - An adhesive sealing film comprises polyisobutylene and tackifying resin. The carbon double bond content of tackifying resin is 1.6-50%. The carbon double bond content in tackifying resin is a ratio of the amount of protons coupled with carbon which is carrying out the double bond to total amount of protons when proton-nuclear magnetic resonance measurement of the tackifying resin is carried out. The total amount of protons contained in tackifying resin is 0.1-8.0 ppm. The amount of protons coupled with carbon is 4.6-8.0 ppm.    USE - Adhesive sealing film is used for organic electroluminescent device (claimed), and inorganic electroluminescent device, solar cell and display.    ADVANTAGE - The adhesive sealing film has high water barrier property, adhesiveness and durability.    DETAILED DESCRIPTION - An adhesive sealing film comprises polyisobutylene and tackifying resin. The number average molecular weight of polyisobutylene is 10000 or more. The carbon double bond content of tackifying resin is 1.6-50%. The concentration of toluene which remains on the adhesive sealing film is 3000 ppm or less. The carbon double bond content in tackifying resin is a ratio of the amount of protons coupled with carbon which is carrying out the double bond to total amount of protons when proton-nuclear magnetic resonance measurement of the tackifying resin is carried out. The carbon double bond content in tackifying resin satisfies a relation: (amount of protons coupled with carbon which is carrying out the double bond in the tackifying resin/total amount of protons in the tackifying resin)x 100. The total amount of protons contained in tackifying resin is the total of the spectrum area of the proton observed by proton-nuclear magnetic resonance measurement, which is 0.1-8.0 ppm. The amount of protons coupled with carbon which is carrying out the double bond is total of the spectrum area of the proton observed by proton-nuclear magnetic resonance measurement, is 4.6-8.0 ppm. INDEPENDENT CLAIMS are included for the following:    (1) manufacture of adhesive sealing film, which involves applying coating liquid containing polyisobutylene and tackifying resin on a base material, and drying; and    (2) coating liquid.    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of organic electroluminescent light-emitting device.    Translucent substrate (1)    Electrodes (2, 4)    Organic functional layer (3)    Sealing layer (5)    Moisture absorption layer (6)