The subject innovation relates to a high-capacity, oxygen-hydrogen mixed gas generating system according to a plurality of variable type electrolytic cell was connected to an electrolytic cell having an electrode plate provided in parallel to the flat plate shape in the inner middle. In the apparatus the subject innovation is provided with a negative electrode and a positive electrode plate in an electrolytic cell, the electrolytic solution by electric decomposition to obtain hydrogen and oxygen gas, and the electrolytic cell body having a flange at the top of the integral portion of the internal space is provided; Inserted into the groove of the insulating base plate having a flat plate shape provided at the inside of the electrolytic cell body +, - the electrode plate and; The temperature sensor and the ball has a cover via a packing of a plurality of bolts and nuts on the cover is secured to the flange top side to be confidential and; +, - while preventing the flow of the electrode plate, and such that power is supplied from the power supply, and an electrode connecting portion provided in the cover to be confidential; Been configured with a gas discharge port and the electrolyte solution inlet provided in the electrolytic cell body is one to safely generate a large gas volume per unit time.