Helium is a colorless, tasteless, and odorless gas that is used as a lifting gas for air balloons and small airships due to its high level of safety. In recent years, it has become easy to search the Internet for methods to commit suicide, and the use of helium gas for this purpose has recently been garnering attention. We report a case of a male in his 30's in which helium gas was used to commit suicide. He was found unconscious on a bed with a plastic bag covering his head. When emergency personnel arrived at the scene, he was in cardiac arrest and remained in cardiac arrest at the time of his arrival at the hospital. Continued cardiopulmonary resuscitation resulted in a return of spontaneous circulation. Head computed tomography showed the corticomedullary border was indistinct. Fifteen hours at the hospital, the patient died. Recently, there has been an increasing trend for suicide being performed according to methods obtained through the Internet or mass media. Although there are only a few cases of suicide by helium gas in Japan, attention must be paid to this issue as the number of such cases may increase in the future.