Described is a roller mill (1) for grinding particulate material such as cement raw materials, cement clinker and the like, said roller mill (1) comprising a grinding table (3), a set of rollers rotatable about a vertical shaft (5), said set of rollers comprising a number of rollers (4) rotating about separate roller shafts (6), which are connected to the vertical shaft (5), and a nozzle ring (7) for directing gases into the roller mill (1), said nozzle ring (7) enclosing the grinding table (3), and means (8) for regulating the gas flow through the nozzle ring (7). The roller mil is peculiar in that at least some of the regulation means (8) are arranged to rotate together with the set of rollers. In order to ensure optimum regulation of the gas flow through the nozzle ring in relation to the uneven load imposed by the material, thereby optimizing the roller mill operation in terms of capacity, grinding efficiency and energy consumption, the position of at least some of the regulation means for regulating the gas flow through the nozzle ring relative to the set of rollers remains the same at all times. The gases which are introduced into the mill via the nozzle ring will, therefore, always exhibit the same flow pattern in relation to the set of rollers.