To provide a method and apparatus for detoxicating halogen compound-containing oil, capable of obtaining dehalogenated oil from which unreacted metal sodium is sufficiently eliminated with a little energy.

The dehalogenated oil obtained by dehalogenating halogen compounds in the oil with metal sodium is introduced to a quenching device 19, is brought into contact with a solid quenching agent 33a having hydroxyl groups on the surface and insoluble to the oil, the unreacted metal sodium remaining in the dehalogenated oil and hydroxyl groups of the solid quenching agent 33a are reacted, and the metal sodium is quenched.