A device provided for taking and continuously analyzing and monitoring breathing gas samples from defined, current phases of breathing of a patient is equipped with a breathing gas line (1) and with a sensor (2) for recognizing the current phases of breathing. A sampling line (3) is provided from the breathing gas line (1). The sampling line (3) is connected to a first gas delivery device (44) via a sample gas loop (4); with a measuring line (8) from the sampling line (3) to a sensor system (6) with a second gas delivery device (66) for the analysis of breathing gas samples; with a valve (5) in the sampling line (3) for controlling the breathing gas sample flow from defined, current phases of breathing into the sensor system (6) and into the sample gas loop (4), and with a control unit (7), which is connected at least to the gas delivery device (44) and to the valve (5), so that a continuous volume flow of breathing gas samples can be fed to the sensor system (6) from the defined, current phases of breathing.