To provide a method and apparatus for detoxicating halogen compound-containing oil, capable of detoxicating halogen compounds in oil such as PCB-containing insulating oil with metal sodium, and effectively eliminating unreacted metal sodium contained in the obtained dehalogenated oil with a little energy.

The PCB-containing insulating oil and metal sodium are reacted in a reaction tank 15, the PCB is dechlorinated to obtain treated oil, thereafter solid impurities such as reaction products and unreacted metal sodium contained in the treated oil are separated using a filtering machine 19, and the unreacted metal sodium still remaining not perfectly being separated is quenched using a solid quenching agent 35.