Chemical decontamination method and chemical decontamination apparatus

A chemical decontamination method comprising:

• a reduction decontamination step of supplying a reduction decontamination solution to a decontamination target portion made of stainless steel;
• performing reduction decontamination on a surface of a member constituting the decontamination target portion;
• a hydrogen peroxide decomposition step of decomposing hydrogen peroxide contained in the reduction decontamination solution after the reduction decontamination step by using a hydrogen peroxide decomposition device which is directly connected to the decontamination target portion via a temporary circulation pipes downstream of the decontamination target portion that decomposes hydrogen peroxide, when an iron concentration in the reduction decontamination solution becomes a predetermined concentration or less;
• and
• a metal ion removing step of removing a metal ion contained in the reduction decontamination solution after the hydrogen peroxide decomposition step by using a metal ion exchange resin tower that removes metal ions, which is installed downstream of the hydrogen peroxide decomposition device and upstream of the decontamination target portion.