A control valve for controlling flow of a pressure fluid in a breaking device includes a sleeve-like control valve having at least one opening enabling flow of the pressure fluid through the opening. The at least one opening includes at least one wall, at least a part of which is not arranged in a direction parallel to a radial direction of the control valve extending through the middle point of the cross section of the opening on the outer circumference of the control valve, such that the pressure fluid flowing through the opening may be arranged to rotate the control valve about the longitudinal axis of the control valve.