A pyrotechnic cutting device has a guiding housing in which there is arranged a part to be severed, which is fashioned so as to be severable at a cut point by a cutting tool having a cutting chisel. A same film material containing Si, O and C is employed in common to form the porous MSQ film 14 and the non-porous MSQ film 17. A deep n-well is located under the isolation region and the striped active area. A convex face of the lens in the box is thus protected against any damage.