Abstract: Apparatus for the pyrotechnic cutting of a submerged tube.The apparatus, which is introduced into the tube, comprises in a conventional manner a chassis on which is mounted a support for a pyrotechnic charge, a shield in the upper part of the chassis and a compressed air intake for producing an air pocket below the shield. According to the invention, the apparatus also comprises a ballast for facilitating its lowering to a considerable depth and the charge is a detonating cord with a hollow charge extending continuously over the support, the clearance between the charge and the inner wall of the tube being of minimum size and the same throughout.