A respirator or anesthesia apparatus for the artificial respiration of a patient is provided with a gas delivery device, at least one gas line for forming a breathing air line system, at least one device for measuring a volume flow of a gas according to the differential pressure method with a flow channel, a first pressure-measuring point and a second pressure-measuring point. The second pressure-measuring point is arranged in the direction of flow of the gas to be measured after the first pressure-measuring point at the flow channel. Furthermore, the flow channel is split into at least two separate partial flow channels in the direction of flow of the gas to be measured between the first pressure-measuring point and the second pressure-measuring point.