The apparatus (1) according to the invention for regulating a process medium flow (2) to be fed to a process medium consumer (28), comprising a) a process medium path (3), by means of which a process medium source (27) can be connected to the process medium consumer (28), and b) a control gas path (4), by means of which a control gas pressure can be built up with a control gas, wherein the process medium path (3) comprises a pneumatic pressure regulator (5), the control input (6) of which is connected to the control gas path (4), wherein means (7) for regulating the control gas pressure are embodied, is distinguished by the fact that the means (7) for regulating the control gas pressure comprise a delivery valve (8) for connecting the control gas path (4) to a control gas pressure source (9) and a discharge valve (10) for decreasing pressure in the control gas path (4). The apparatus (1) according to the invention and the method according to the invention advantageously permit precise regulation of the process medium flow (2) from a process medium source (27) to a process medium consumer (28) using simple means. On account of the magnetic valves (8, 10, 19) used such as, for example, the magnetic 5/3-way directional valve (19) for increasing or decreasing a control gas pressure in a control gas path (4), corresponding regulation can even be used in areas at risk of an explosion, such as, for example, in ultra-clean rooms, in implanters (18) or the like.