A low common salt soy sauce, which has good flavor, significantly suppresses elevation of blood pressure, prevents cardiac hypertrophy, and is also available as special nutritious food, is obtained. 1.0% to 10.0% by weight of potassium chloride and 0.1% to 5.0% by weight of .gamma.-aminobutyric acid are added to a reduced common salt soy sauce, so as to obtain a low common salt soy sauce of issue. Otherwise, a KCl-containing low common slat soy sauce is obtained by: (1) a common production method of soy sauce, in which a mixed solution consisting of KCl and common salt is used as mother water; (2) a method of subjecting a soy sauce obtained using saline solution as mother water to electrodialysis, a membrane treatment, or the like, so as to eliminate common salt from the above soy sauce, and then adding KCl thereto; or other methods. Thereafter, .gamma.-aminobutyric acid is added to the above KCl-containing low common salt soy sauce, so as to obtain a low common salt soy sauce comprising 0% to 10% by weight of common salt, 1.0% to 10.0% by weight of potassium chloride, and 0.1% to 5.0% by weight of .gamma.-aminobutyric acid.