Chemical reactivities of the metal complexes of thiohydroxamic acids was investigated. By alkylation or acylation, all the metal complexes except the nickel complex was dissociated to the corresponding metal ions and derivatives of thiohydroxamic acid. The nickel complex was benzoylated without undergoing the dissociation in chilled sodium hydroxide. Sodium or zinc salts or some derivatives of benzothiohydroxamic acid underwent the Lossen rearrangement, and the rearrangement products were isolated. However, the nickel complex did not give the rearrangement products in alkaline solution because of the stability of the chelated structure. From those results, it was confirmed that the hydroxyimino group of thiohydroxamic acid is in the syn configuration to the sulfur atom and that the transition metal complexes possess the five-membered chelate structure as shown in formular [chemical formula] (M=metal ion) in the solid state.