An impact fuse includes a body containing a piezoelectric generator positioned on a bracket integral with the body. The piezoelectric generator serving as an anvil. The fuse includes a piston intended to mechanically contact the generator upon impact. The piston receives the impact forces transmitted by a cap. The fuse being characterized in that the piston is slidably fitted within the body and in that it includes plastically deformable means that are interposed between the cap and the body. The means are deformed by cap movement upon impact with a target via piston movement. The plastically deformable means is configured to be deformed in a manner that causes the piston to more gradually exert force on the piezoelectric generator.