A device for controlling a volumetric flow rate of a medium stored under pressure in order to activate an impact protection device, having a control module that includes a valve body having a stepped through-opening, and a control piston guided axially in the through-opening of the valve body, and a control valve that influences the movement of the control piston, the valve body having at a first end a closable medium inlet opening having a valve chamber. The control valve and the control module are situated in a common housing sleeve, the valve body of the control module being pressed into a first end of the housing sleeve until it comes to a stop on a housing shoulder, and the control valve being introduced into and fixed in a second end of the housing sleeve.