A method for controlling gas leak includes a step of providing gas for a pre-set period of time automatically; a step of cutting off gas supply automatically by cutting off electric power for the electro-magnetic valve so that the piston of the electro-magnetic valve seals an opening of an inlet path; a step of checking gas leak by using a pressure detection device in the safety valve to check gas pressure after the gas is filled in the safety valve and the pipe for a period of time, the pressure detection device transferring detected signals to a circuit board, and the detected signals being used as a basis of judgement of gas leak, and a step of supplying gas again and checking the pressure by the pressure detection device.