PROBLEM TO BE SOLVED: To provide a hydrogenation method or the like capable of producing hydrogenated water having a high dissolved hydrogen concentration with a simple configuration. SOLUTION: The hydrogen addition method includes a first step S1 for generating dissolved hydrogen water containing hydrogen gas in a bubble state, a second step S2 for supplying the dissolved hydrogen water to one side of a reverse osmosis membrane, and dissolved hydrogen. The third step S3 in which water is permeated to the other side of the reverse osmosis membrane, the fourth step S4 in which hydrogen gas is miniaturized by the reverse osmosis membrane and permeated to the other side, and the micronized hydrogen gas is contained in the other side. The fifth step S5 for obtaining the dissolved hydrogen water to be obtained is included. [Selection diagram] Fig. 6【課題】簡素な構成で、溶存水素濃度の高い水素付加水を生成できる水素付加方法等を提供する。【解決手段】水素付加方法は、水素ガスが気泡状態で含まれる溶存水素水を生成する第１工程Ｓ１と、溶存水素水を逆浸透膜の一方側に供給する第２工程Ｓ２と、溶存水素水を逆浸透膜の他方側に透過させる第３工程Ｓ３と、水素ガスを逆浸透膜によって微細化し、他方側に透過させる第４工程Ｓ４と、他方側で、微細化された水素ガスが含まれる溶存水素水を得る第５工程Ｓ５とを含む。【選択図】図６
