The present invention relates to a manufacturing method of medical sterilized normal saline, more specifically, to such a method for manufacturing sterilized normal saline for medical purpose with effective sterilizing efficacy comprising: a step of disposing at least one electrode set immersed in saline solution of pH 4.0 to pH 7.5 including a pair of electrodes with flat surface separated from each other by an interval between 1 mm and 3 mm, the flat surfaces of the electrodes facing each other and a step of supplying 30 mA to 200 mA direct current to the electrodes by applying 2.4V to 3.3V DC power to the electrodes wherein free chlorine is reliably and stably generated as having concentration range between 0.17 ppm and 6 ppm from electrolysis between electrodes.
