NOVELTY - To provide an electrolyzer capable of generating a mixed gas of hydrogen and oxygen stably and efficiently by stably supplying a proper quantity of water into the electrolyzer and installing a double backfire preventer for prevention of backfire, and an apparatus for generating the mixed gas of hydrogen and oxygen by adopting the electrolyzer.    DETAILED DESCRIPTION - An apparatus (10) for generating mixed gas of hydrogen and oxygen comprises: an electrolytic part (100) comprising a plurality of electrolyzers (100a,100b,100c) for outputting produced mixed gas of hydrogen and oxygen by electrolyzing water, thereby producing a mixed gas of hydrogen and oxygen; a power supply part (200) for supplying a DC power source to the electrolytic part; a pressure control part (600) for outputting the produced the mixed gas by producing a mixed gas of hydrogen and oxygen having certain pressure in the electrolytic part; a backfire prevention part (700) for preventing flame in the outside from being backfired to the electrolyzers; and a control part (800) for controlling action of the electrolytic part by controlling power supply according to pressure of the mixed gas coming out of the electrolyzers after being produced in the electrolyzers and controlling the electrolyzers to prevent the mixed gas from being overheated according to inner and outer temperature values of the electrolyzers, wherein the apparatus further comprises an automatic water supply tank (300), a water level sensor and a solenoid valve, wherein the apparatus further comprises an electrolyte temperature sensor, an electrolyzer temperature sensor and a cooling fan, wherein the control part comprises a power supply control part, a cooling fan driving switch and a water level control switch, wherein the backfire prevention part comprises a water sealing type backfire preventer (710), a dry type backfire preventer (720), a moisture remover (730) and a flame controller (740), and wherein the pressure control part comprises a first pressure detector (610) and a second pressure detector (620). (C) KIPO 2006 Image 1/1