As a unit which functions to prevent variations in the respiration phases of a user, erroneous recognition due to disturbances such as vibrations of the supply unit and wind, discomfort to the user due to unnecessary supply of oxygen and wasteful supply of oxygen, there is provided a respiration-synchronizing gas supply unit characterized by comprising means for recognizing the inspiration phase initial point and the expiration phase initial point, and by carrying out automatic on-off valve control with recognition means that does not recognize the next inspiration phase initial point during the time between recognition of the inspiration phase initial point and recognition of the expiration phase initial point, and between recognition of the expiration phase initial point and elapse of a predetermined time period. <；IMAGE>；
