Provided are a bioactivation method for enhancing a neural activity and/or a blood circulation activity of a living body and a hydrogen generating device for executing this method. In the method, a gas mixture containing hydrogen and oxygen at predetermined concentrations is suctioned by spontaneous breathing continuously for a predetermined time. Moreover, this hydrogen generating device for executing the bioactivation method for enhancing a neural activity and/or a blood circulation activity of a living body includes a body cover member including a battery, a control substrate for controlling power supply from the battery, and a pair of positive/negative electrodes electrically conducted with or shut down from a positive electrode and a negative electrode of the battery by the control substrate.