NOVELTY - A back surface protection sheet (A) has sealing layer (4) which is integrally laminated on surface of a lamination sheet (B) in which vapor deposition film (2) and secondary weather-resistant base material (3) of inorganic oxide are integrally laminated on primary weather-resistant base material (1) in order. The sealing layer contains 100 pts. wt. modified polypropylene-type resin having melting point of 120-170 degrees C based on JIS K7121, and 0.001-20 pts. wt. silane compound (I).    USE - Back surface protection sheet is used for solar cell module (claimed).    ADVANTAGE - The back surface protection sheet has excellent flexibility and heat resistance. The solar cell module is efficiently manufactured using the back surface protection sheet. The generation of decomposition product of organic peroxide is prevented such that the adhesiveness of the back surface protection sheet is maintained for long period of time.    DETAILED DESCRIPTION - A back surface protection sheet has sealing layer which is integrally laminated on surface of a lamination sheet in which vapor deposition film and secondary weather-resistant base material of inorganic oxide are integrally laminated on primary weather-resistant base material in order. The sealing layer contains 100 pts. wt. modified polypropylene-type resin having melting point of 120-170 degrees C based on JIS K7121, and 0.001-20 pts. wt. silane compound of formula: R1Si(OR2)3 (I). The modified polypropylene-type resin is graft-modified with unsaturated carboxylic acid or its anhydride.    R1=non-hydrolyzable and polymerizable functional group;and    R2=1-5C alkyl.    An INDEPENDENT CLAIM is included for solar cell module, which has thin-film solar cell having solar cell element formed on the surface of a transparent substrate, and back surface protection sheet is integrally laminated on the sealing element.    DESCRIPTION OF DRAWING(S) - The drawing shows a longitudinal cross-sectional view of the back surface protection sheet.    Primary weather-resistant base material (1)    Vapor deposition film (2)    Secondary weather-resistant base material (3)    Sealing layer (4)    Back surface protection sheet (A)    Lamination sheet (B)