Provided are a thermosetting adhesive composition excellent in storage stability, reliability, and low-temperature adhesion properties; and a curl-resistant heat-resistant film and a wiring film obtained using the composition. The thermosetting adhesive composition includes 100 parts by weight of a phenoxy resin having a bisphenol S skeleton in the structure thereof; 5 to 30 parts by weight of a maleimide compound containing a plurality of maleimide groups in the structure thereof; and 3 to 20 vol % of an inorganic needle-like filler. The heat resistant adhesive film is obtained by applying the thermosetting adhesive composition onto a polyimide film, followed by drying. The wiring film is obtained by placing a conductor wiring layer on the heat resistant adhesive film.