A regulating device comprising an electronic control unit for regulating boost pressure in a supercharged internal combustion engine with two-stage supercharging, i.e. with a first low-pressure stage (ND) and a second high-pressure stage (HD). The high-pressure stage (HD) has a rigid high-pressure turbine and a controllable regulating flap (RK). The low-pressure stage (ND) has a variable adjustable turbine geometry (VTG). The electronic control unit contains a regulating module that is designed, in particular via an appropriately programmed computer program product, for basic adjuster regulation in such a way that the boost pressure regulation is carried out solely by way of the adjustable turbine geometry (VTG) of the low-pressure stage (ND), wherein the regulating flap (RK) of the high-pressure stage (HD) is controlled in the fully closed state.