NOVELTY - A resin composition (A) containing organic peroxide and ethylene-based copolymer, is supplied melt-kneaded and extruded. A resin composition (B) is supplied to an extruder (II). Lamination integration of resin composition (B) is carried out on both surfaces of resin composition (A), after joining opposing both ends to obtain laminated sheet. The laminated sheet is extruded and expanded, and co-extrusion of intermediate sheet layer (B) containing composition (A) and outer sheet layer (C) containing composition (B) is carried out to obtain an adhesive sheet (A).    USE - Manufacture of adhesive sheet for solar cell.    ADVANTAGE - The adhesive sheet is stably manufactured with uniform thickness, and reliably enables pressure-bonding integration of solar cell element and protection element. The adhesive sheet has improved heat resistance and excellent adhesiveness for long period of time. The solar cell is obtained with high durability using the adhesive sheet.    DETAILED DESCRIPTION - A resin composition (A) containing an organic peroxide and ethylene-based copolymer as main component, is supplied to an extruder (I), melt-kneaded and extruded. A resin composition (B) is supplied to an extruder (II) different from extruder (I). The resin composition (B) is resin composition containing organic peroxide and scorch retarder, and having low cross-linkability with respect to composition (A), or a resin composition containing ethylene-based copolymer, does not having cross-linkability and does not containing organic peroxide. The resin compositions (A,B) are joined. Lamination integration of resin composition (B) in sheet form is carried out on both surfaces of resin composition (A) in sheet form, after joining opposing both ends in width direction of composition (B) to obtain laminated sheet. The laminated sheet is supplied to T die to which the extruder is connected. The laminated sheet is expanded in width direction within T die. Co-extrusion of intermediate sheet layer (B) containing resin composition (A) and outer sheet layer (C) containing resin composition (B) and covering the intermediate layer is carried out to obtain an adhesive sheet.    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of lamination state of adhesive sheet.    Adhesive sheet (A)    Intermediate sheet layer (B)    Outer sheet layer (C)