To provide a method and apparatus for detoxicating halogen compound-containing oil, capable of more effectively neutralizing dehalogenated oil.

The apparatus 1 for detoxicating PCB-containing insulating oil has a holding tank 11 for holding the oil to be treated, a depressurizing distilling tank 13 for removing water contained in the oil to be treated, a reaction tank 15 for reacting the PCB with metal sodium and dechlorinating the same, a decomposition confirming tank 17 for confirming the dechlorination of the PCB, a filter device 19 for separating solid impurities contained in the oil to be treated, and a neutralizing device 21 directly dissolving carbon dioxide gas into the treated oil from which the solid impurities are separated and neutralizing the treated oil.