An explosive powder operated setting device uses the propellant gases from an ignited explosive powder charge for driving a piston which, in turn, propels a fastening element from the device into a receiving material. The device includes a housing, a barrel mounted in the housing with the piston displaceably mounted in the barrel. A tubular-shaped slide valve is rotatably mounted in the rear portion of the barrel behind the piston. The front end of the slide valve combines with the barrel in forming a space in which the propellant gases contact the piston and drive it through the barrel. The rear end of the slide valve forms a part of the combustion chamber within the device. At its front end, the slide valve is frusto-conically shaped and forms a seal with a correspondingly shaped surface in the barrel. An exhaust duct section extends through the barrel and is in communication with another exhaust duct section in the housing. The slide valve has exhaust openings extending radially through it which can be aligned with the exhaust duct section in the barrel so that, if required, a part of the propellant gases can be exhausted to the atmosphere without being used for driving the piston.