We propose Flammable Gas Leak Detector, which is engineered for constantly monitoring for hazardous concentration of gases. It has facility for simply connection of buzzer/hooter for alarm by means of relay. Plus, it has a small size electronic module which is perfectly housed in an explosion proof or weatherproof polyester or metallic box with a usage specific sensor. The presented advanced technology device is carefully engineered and manufactured with selected industrial grade components for ensuring its high accuracy, reliability, and long life. Further, Flammable Gas Leak Detector is fitted with micro-controller and featured with featured with self-diagnostics, and auto calibration through embedded software.