The present invention provides an optical-use pressure-sensitive adhesive sheet, which includes a pressure-sensitive adhesive layer containing a polymer formed of one or more monomer ingredients containing, as an indispensable monomer ingredient, a monomer of which homopolymer has a glass transition temperature of not lower than −10° C., said sheet having a moisture content of at least 0.65% by weight after stored in an environment at 60° C. and 95% RH for 120 hours. The pressure-sensitive adhesive layer is preferably an acrylic pressure-sensitive adhesive layer.