A pyromechanical disconnecting device, in particular for battery shutoff in a motor vehicle include a housing (1) in which there is arranged a conductor bus (11) that is designed to be severable by a cutting chisel (12) at a predetermined cut point, the cutting chisel being capable of being accelerated by the propellant gases of an ignition element (2). In order to facilitate assembly it is proposed that the housing (1) be extruded around the ignition element (2), which in this way forms one structural unit with the housing (1).