Abstract: The invention relates to a method for thermally initiated triggering of an aerosol fire extinguisher having a strike pin (6) acted upon by an inner spring (7) and locked in the stand-by state, and after thermal initiation, the lock is removed and the strike pin (6), driven by the force of the inner spring (7), strikes against a mechanical firing cap (1), whereby an initial firing material is released in the firing cap (1), igniting a booster charge (2), the hot conversion gas thereof igniting a pyrotechnic extinguisher charge in the aerosol fire extinguisher. In order that an absolutely reliable initiation takes place under the same conditions throughout the entire service life of the aerosol fire extinguisher, it is proposed that only immediately after the thermal initiation, when the firing pin (6) is still locked, the inner spring (7) is brought to the necessary tension for triggering the firing cap (1), and only after reaching said tension is the lock of the firing pin (6) automatically released.