PROBLEM TO BE SOLVED: To provide a hydrogen gas supply apparatus for a living matter in which hydrogen gas beneficial in health can be safely used in a field of medical care and household.SOLUTION: A hydrogen gas supply apparatus for a living matter includes: an electrolysis tank 1 that includes an electrolytic chamber 11 in which a raw water to be electrolyzed 12 is introduced, at least one barrier membrane 13 that blocks an inside and an outside of the electrolytic chamber, and at least one pair of electrode plates 14, 15 disposed respectively in the inside and the outside of the electrolytic chamber to pinch the barrier membrane, and in which an electrode plate of the outside of the electrolytic chamber is disposed to contact the barrier membrane； a direct current power source 2 that applies direct current voltage to the pair of electrode plates； and a dilution gas feeder 3 that dilutes hydrogen gas generated from an electrode plate becoming a cathode, wherein dilution gas supplied from the dilution gas feeder is ventilated to the cathode or the cathode water surface, thereby hydrogen gas concentration of the cathode vicinity at electrolysis is maintained at any time less than 18.3 vol.%, and a mixed gas including hydrogen gas and dilution gas in which hydrogen gas concentration is 4-18.3 vol.% is supplied to a living matter.【課題】健康上有益な水素ガスを医療の現場や家庭で安全に使用することができる生体用水素ガス供給装置を提供する。【解決手段】被電解原水１２が導入される電解室１１と、前記電解室の内部と外部とを区画する一つ以上の隔膜１３と、前記電解室の内部及び外部のそれぞれに前記隔膜を挟んで設けられた少なくとも一対の電極板１４，１５と、を有し、前記電解室の外部の電極板が前記隔膜に接触させて設けられている電解槽１と、前記一対の電極板に直流電圧を印加する直流電源２と、陰極となる電極板から発生する水素ガスを希釈するための希釈用ガス供給器３と、を備え、前記希釈用ガス供給器から供給される希釈用ガスを前記陰極又は陰極水面に送風することにより、電解時の前記陰極近傍の水素ガス濃度を常に１８．３vol％未満に維持し水素ガス濃度が４～１８．３vol％の、水素ガスと希釈用ガスを含む混合ガスを生体に供給する。【選択図】図１
