Magnet-thermocouple for the fail-safe safety supply of gas to burners or the like, in particular of fail-safe safety control for domestic cooking devices, comprises: at least one gas burner, which gas burner is connected to a gas supply source by flame-regulating means and by means of a safety valve driven by a flame presence sensor consisting of a thermocouple, said safety valve having an open condition, wherein said supply source supplied said burner, and a closed condition, wherein the gas passage is interrupted and wherein the thermocouple, in the presence of a flame, generates an electrical signal constituting the drive signal for the passage of said safety valve from an open condition to a closed condition, and vice-versa, of said safety valve, whereas a further drive signal generator and power supply of said safety valve is provided, for the temporary and alternative supply of the safety valve during the flame ignition step heating the thermocouple, to the temperature generating the drive signal. According to the invention, the signal generator and power supply comprise power limiters to limit the signal generated and an automatic deactivating unit whenever the power supply is overloaded for a predefined amount of time, the power necessary for the drive signal of the safety valve being greater than the one determined by the limiters.