In a solution containing the polar solvent such as pyridine, quinoline, dioxane, dimethylformamide, and dimethylsulfoxide, sulfamic acid and its N-substituted derivatives were converted to an equimolar amount of inorganic sulfate and corresponding amine. The factors and the reaction mechanisms concerning this degradation process were discussed on the basis of the experimental results, and the following scheme of the reaction was proposed : [chemical formula] It was also proved that this reaction and the determination procedures is possible to apply as the general analytical method for sulfamic acid derivatives.