Provided is an adhesive which enables the formation of a packaging material for batteries, said packaging material having excellent moldability and high adhesive strength even after long-term endurance test. A polyurethane adhesive for packaging materials for batteries according to the present invention contains a base material and a polyisocyanate curing agent. The base material contains: (A) a polyol component that contains (A1) a polyester polyol having a glass transition temperature of 40 DEG C or more and (A2) a polyester polyol having a glass transition temperature less than 40 DEG C at a specific composition ratio; and (B) a silane coupling agent. The equivalent ratio of the isocyanate groups contained in the curing agent relative to the total of the hydroxyl groups and carboxyl groups derived from the polyol component (A), namely [NCO]/([OH] + [COOH]) is set to be 10-30.