FIELD: electrochemistry; may be used in flame machining of materials. SUBSTANCE: production method of oxygen and hydrogen by water electrolysis consists in that applied to electrolyzer cells is voltage from DC source. First, voltage is applied to n cells and then, additionally, m cells are energized. Device for the method embodiment has DC source connected to electrolyzer including n + m electrolytic cells connected in series and switch. Switch inlet is connected with one of poles of DC supply source and one outlet is connected to nth electrolytic cell and the other, to (n+m)th cell. EFFECT: higher productivity and power utilization factor. 2 cl, 1 dwg
