Thermosetting adhesive composition and thermosetting adhesive sheet

A thermosetting adhesive composition which contains (A) an acrylic rubber, (B) at least one crosslinking agent that is selected from the group consisting of isocyanate crosslinking agents, blocked isocyanate crosslinking agents and amine crosslinking agents and (C) a ferromagnetic body. This thermosetting adhesive composition preferably contains the ferromagnetic body (C) in an amount of 150-600 parts by mass relative to 100 parts by mass of the acrylic rubber (A). This thermosetting adhesive composition exhibits temporary fixing force due to magnetic attraction in the initial stage, and exhibits adhesiveness after thermal setting, while having large shear force and excellent heat resistance.