A method for producing a flexible packaging film including a substrate and a polyurethane adhesive that is applied to the substrate and is a mixture of an A agent and a B agent includes a two-part separate application step that includes bringing a mixture of the A agent and B agent applied to one substrate into contact with a catalyst applied to another substrate and pressing the substrates, wherein the A agent is a polyisocyanate compound, and the B agent is a polyol compound. The polyol compound is preferably a polymer polyol comprising a polyether polyol or a polyester polyol as an essential component.