The present invention provides a sheet for sealing a rear surface of a solar cell in which degradation due to hydrolysis of the material constituting the solar cell is prevented, and the weather resistance is excellent such that electric output properties of the solar cell can be maintained not only under conditions of actual usage of the solar cell module but also conditions for evaluation under high temperatures and high moistures, and provides a sheet for sealing a rear surface of a solar cell comprising a laminate in which at least two substrates are laminated by an polyurethane-based adhesive, wherein the polyurethane-based adhesive comprises an adhesive having hydrolysis resistance which satisfies the following conditions: condition 1: the lamination strength of the adhesive is 1 N/15 mm or more after keeping the laminate in a chamber which acts as a highly accelerated stress test system under pressurized steam conditions of 105° C. and 1.05 atm for 168 hours; and condition 2: the adhesive does not bring on a delamination and a blister between the substrates after keeping the laminate in a chamber which acts as a highly accelerated stress test system under pressurized steam conditions of 105° C. and 1.05 atm for 168 hours.