Abstract: Disclosed is a method for storing hydrogen, a method for generating hydrogen, a hydrogen storing device, and a hydrogen generating device. In a disclosed method for storing hydrogen, water that is treated so as to include hydrogen ions in a state the ions can be changed into protium is prepared, and hydrogen is stored by supplying a hydrogen-containing substance or a substance that generates hydrogen, for example, Mg, into the water. Preferably, the hydrogen-containing substance is sodium borohydride (NaBH4). Preferably, the water is ionized hydrogen water treated with a metal hydride, and the metal hydride is at least one among an alkali metal, an alkaline earth metal, a group 13 metal, and a group 14 metal.