An oxygen concentrator 10 includes an oxygen generation unit 12 configured to generate oxygen, an oxygen discharge unit 13 configured to discharge the oxygen generated by the oxygen generation unit 12, a respiration waveform sensor 20 connected to at least one of a passage 14 and a cannula 2, and a respiration waveform storage unit 21 configured to store a respiration waveform detected by the respiration waveform sensor 20. The passage 14 connects the oxygen generation unit 12 to the oxygen discharge unit 13. The cannula 2 is attached to the oxygen discharge unit 13.
