Improved process for the preparation of a nitroisourea derivatives

To provide an improved method for producing a nitroisourea derivatives required for the preparation of nitroguanidine derivatives having an insecticidal activity. Generally, it characterized and nitroisourea compound represented by the general formula (1), general formula amine or a salt thereof (2), the coexistence of bicarbonate of a catalytic amount, to react method for producing nitroisourea derivatives represented by the formula (3).