The present invention provides a light and thin backside covering material for a solar cell module which is excellent in moisture resistance and durability and has a good insulator without causing a short circuit with underlying wire nor leak current. Also the invention provides a durable and high performance solar cell module using this backside covering material as a rear surface protection member. The backside covering material for a solar cell module is a three-layer laminated film, wherein a moisture resistant film is sandwiched with two films having heat resistance and weather resistance. A deposited layer 5 of inorganic oxide is formed on a surface of a base film 4 to make the moisture resistant film 3.