An adhesive film characterized by a film-like composite base material was patented. The film has at least a first resin film with a breaking elongation in the lengthwise direction of 300 to 1500% and a breaking strength of at least 2 kg/12 mm. The film also features a second resin film with a lower breaking elongation and a higher flexural modulus than the first resin film. An adhesive layer is formed on at least one side of the composite base material. The second resin film includes a dispersed filler in a form of needle-like whiskers. When stretched, the second resin film breaks before the first resin film.