A composition curable with actinic energy rays is provided with which it is possible to produce a back protective sheet for solar cells that has excellent adhesion between sheet members and excellent moist-heat resistance, in a high yield with high productivity at low cost. This adhesive comprises a urethane resin (D) and an epoxy resin (E). The urethane resin (D) is obtained by reacting a diol ingredient (A1) having no (meth)acryloyl group, a diol ingredient (A2) which is an optional ingredient and has neither a (meth)acryloyl group nor a carbonate structure nor an alicyclic structure, a polyol ingredient (B) having a (meth)acryloyl group and two or more hydroxy groups in the molecule, and a polyisocyanate ingredient (C). The ingredient (A1) is selected from a diol (a1) having a carbonate structure and an alicyclic structure in the molecule, a combination of a diol (a2) having no alicyclic structure but having a carbonate structure and a diol (a3) having no carbonate structure but having an alicyclic structure, and a combination of the diol (a1) and at least the diol (a2) or the diol (a3).