The objective of the present invention is to allow a hydrogen gas which has a gas mixture concentration of over 4% to be breathed in safely, and to reduce the amount of use of hydrogen gas, which is dangerous, and increase utilization efficiency of the hydrogen gas. The objective of the present invention is also to impart an auxiliary role to a device in the treatment of patients suffering from viral or bacterial pneumonia using hydrogen gas. A hydrogen gas mixture breathing device and a related system employ an intrinsically safe structure and a safety system which prevent occurrence of explosions. A detonation flame arrester, etc. are installed where necessary to provide against electrostatic explosions, etc., and to protect a users lung function from explosion flames. In addition, a device for supplying aerosol in which a hydroxyl radical is dissolved is also installed, and operating time and volume are appropriately adjusted under the supervision of a professional. Depending on the circumstances, the content of the aerosol is changed to microdroplets that comprise a bivalent iron ion or monovalent copper ion. Suction of a hydrogen-rich gas mixture and suction of the aerosol take place alternatively according to a program and not simultaneously.
