NOVELTY - A solar cell back sheet (1) has polymer base material (10), pigment layer (12) containing binder and pigment provided on the primary surface of the polymer base material, topcoat layer (14) containing binder provided on the pigment layer, and composite polymer layer (16) provided on the secondary surface of the polymer base material. The composite polymer layer contains composite polymer (I) containing 15-85 %mass of siloxane structural unit and 85-15 %mass of non-siloxane-type structural unit in a molecule.    USE - Solar cell back sheet is used for solar cell module (claimed).    ADVANTAGE - The solar cell back sheet has excellent reflection property, durability, and adhesiveness with respect to sealing material, and is manufactured economically. The solar cell module containing back sheet has favorable electric power generation efficiency.    DETAILED DESCRIPTION - A solar cell back sheet has polymer base material, pigment layer containing pigment and binder provided on the primary surface of the polymer base material, topcoat layer containing binder provided on the pigment layer, and composite polymer layer provided on the secondary surface of the polymer base material. The composite polymer layer contains composite polymer of formula: (-Si(-R1)(-R2)-O-)n (I) containing 15-85 %mass of siloxane structural unit and 85-15 %mass of non-siloxane-type structural unit in a molecule.    R1,R2=H, halo or monovalent organic group;and    n=1 or more.    INDEPENDENT CLAIMS are included for the following:    (1) manufacture of solar cell backsheet, which involves melt-extruding raw resin to a sheet form, cooling melt-extruded sheet-like resin, forming resin sheet into a film, carrying out extending process which stretches the resin sheet along the direction (D1), coating at least single side of the stretched resin sheet to form undercoat, and carrying out extending process which stretches the undercoated resin sheet along the direction (D2) which is orthogonal to the direction (D1); and    (2) solar cell module, which has transparent substrate with which sunlight injects, solar cell element and solar cell backsheet.    DESCRIPTION OF DRAWING(S) - The drawing shows the schematic sectional view of the solar cell backsheet.    Solar cell back sheet (1)    Polymer base material (10)    Pigment layer (12)    Topcoat layer (14)    Composite polymer layer (16)