Hydraulic percussion hammer, in which a motion of a percussion piston (1) is controlled by a main valve (3), the control motion of which is controlled by a separate control valve (9) in such a way that the main valve changes its state, when the pressure acting on the control valve (9) rises to a predetermined value. The percussion hammer comprises a controller (21) mounted in its return duct (13), by which controller an outflow of pressure fluid from the percussion hammer can be adjusted in such a way that the filling rate of a pressure accumulator (7) and thus the length of a return motion of the percussion piston (1) are proportional to the flow resistance provided by the controller (21).