A respiratory waveform analyzer (10), operable to analyze a respiratory waveform, which is generated based on a temporal change of a concentration of a component in respiratory gas of a subject, the respiratory waveform analyzer (10) comprising: a respiratory airway adaptor (20) in which the respiratory gas of the subject flows, the respiratory airway adaptor (20) provided with a sensor (50) that measures the concentration of the component to output a signal a respiratory gas concentration generator (100, 210) which generates a concentration signal based on the signal output by the sensor (50), the concentration signal indicating degree of the concentration and a liquid detector (280) which detects a liquid in the respiratory airway adaptor based on the concentration signal.
