The roller mill according to the invention consists substantially of two grinding rollers which are driven in opposite directions and form between them a grinding gap for comminuting material to be ground, and a delivery chute via which the material to be ground is fed to the grinding gap. Furthermore, there is provided in the delivery chute a pressure sensor for measuring the static gas pressure, which pressure sensor is connected to a control or regulating device, which changes the circumferential speed of the grinding rollers in dependence on the measured static gas pressure. In the method according to the invention for operating the above roller mill, the static gas pressure in the delivery chute is measured and used to control or regulate the circumferential speed of the grinding rollers.