To provide an incineration ash detoxification treatment process which enables inhibition of environmental pollution due to pollutants derived from or contained in municipal solid waste and/or general incineration ash, such as heavy metals and dioxins while subjecting generated off-gas to detoxification treatment and also to provide an equipment for the process.

This detoxification treatment process comprises: subjecting incineration ash to dehydration/drying and grinding treatment; and detoxifying the treated incineration ash in a space which is isolated from the outside air and maintained in such a state that the oxygen concentration in the space is low, by subjecting toxic substances in the incineration ash to reduction treatment to detoxify the toxic substances and converting heavy metals in the incineration ash into stable compounds.