An adhesive film for metal terminals is interposed between a metal terminal connected to an electrode of a power storage device element and a power storage device external member, and includes, a first polyolefin layer, a substrate, and a second polyolefin layer disposed on the metal terminal side. A sea-island structure is observed in a sectional image of the first polyolefin layer in a direction parallel to TD, the sectional image being obtained in the range of up to 30% of the thickness of the first polyolefin layer. In the sectional image, after the adhesive film for metal terminals is left to stand for 12 seconds in a heated and pressurized environment in which the temperature is 190° C. and the surface pressure is 0.016 MPa, and then left for one hour at 25° C., the of the total area of the island portions of the sea-island structure is 25.0% to 35.0%.