A method for manufacturing a high-flavor fish sauce within a short period of time and a fish sauce prepared by the method. The method for manufacturing a fish sauce includes fermenting a salted marine product for the first time and then performing fermentation/ripening under a constant-temperature condition after adding a crude fish sauce, and can considerably reduce the long fermentation and ripening period, which is 1-3 years or longer, of the traditional method. Also, since the fish sauce prepared by the method for manufacturing a fish sauce has improved nutrient content and taste, with reduced characteristic fishy odor and improved sensory flavor and quality, it is highly competitive and can be widely used in the fish sauce manufacturing industry.