Disclosed is a sheet member for solar cells which is composed of resin films only without using a resin film on which an aluminum foil or oxide is vapor-deposited and still has practical barrier properties, excellent impact resistance and excellent water resistance. Specifically disclosed is a back sheet (10) which is a sheet member for solar cells that is arranged on the back side of a solar cell module (100). The back sheet (10) is composed of a plurality of resin films (11, 12, 13) which are divided into inner layers which are arranged relatively near the solar cell module and outer layers which are arranged relatively far from the solar cell module, and the outer layers include a polyethylene naphthalate (PEN) film.
