It is widely known that a fire was caused by an electrical cause of the compressor-driven relay installed in the kimchi refrigerator manufactured before september 2005. However, there is no case of concretely demonstrating the mechanism of fire in the relay. Accordingly, this study analyzed the fire case of a kimchi refrigerator and confirmed the cause of the relay’s ignition through a fire reproduction experiment. First of all, PCBs were collected for each year of W company’s products where fires frequently occur, and the structural differences of relays were compared using X-rays. Afterwards, it was confirmed that the relay was fired due to structural causes by the repeat opening/closing test on the relay. In addition, from the actual fire test, it was proved that if ignited in the relay, the fire could spread to the entire kimchi refrigerator. Finally, based on the research results, a fire investigation technique for kimchi refrigerator were presented