The Standalone Natural Gas Alarm is a product which combines natural gas detection and local high-decibel alarm together, integrating catalytic-type sensors to accurately detect the leakage of natural gas, especially methane, and send out effective notification to prevent explosions and notice users. The product integrates two alarm output ports, when gas leakage is detected, it can link the electric solenoid valve, automatic shut-off manipulator and exhausting fan to cut off the gas source in time and reduce the concentration of the leaked gas. This product can be widely used in kitchens, restaurants and heating equipment rooms.