An aminoalkylthiosulfuric acid compound represented by formula (1): is produced. In step (A1), a hydrochloride of a chloroalkylamine compound represented by formula (2): is reacted with an alkali metal salt of thiosulfuric acid in the presence of 2 to 6 parts by weight of water with respect to 1 part by weight of the hydrochloride between 50° C. and 100° C. R1 and R2 each represents a hydrogen atom and the like, and n represents an integer of 2 to 9. In step (B1), a mixture of a solid containing the aminoalkylthiosulfuric acid compound and a liquid containing an alkali metal chloride is obtained by adjusting the temperature of the mixture of step (A1) to between −15° C. and 50° C. In step (C1), the aminoalkylthiosulfuric acid compound is obtained as solid by separating the solid containing the aminoalkylthiosulfuric acid compound and the liquid containing the alkali metal chloride from the mixture of (B1).