A device for generating pressure pulses, includes a pressure fluid source and a pressure fluid depression, a pressure fluid circuit, a valve body displaceably located in a chamber, a first branch and a second branch the branches leaving to opposite sides of the valve body, the chamber having an opening on one side of the valve body, the opening communicating with the first branch and permitting pressure fluid to flow out of the chamber. The valve body, under the action of the pressure fluid in the branches, is displaceable to a first position in which it closes the opening and to a second position in which it leaves the opening open for out-flow of the pressure fluid. The device includes a first valve member arranged to permit or interrupt communication between the chamber and the pressure fluid source through the second branch upstream of the chamber.