PROBLEM TO BE SOLVED: To provide a seasoning capable of efficiently conferring, onto a seasoning sauce, rich, delicious, and mellow flavors of a demi-glace sauce.SOLUTION: The provided method for manufacturing a seasoning sauce includes a step of preparing a miso seasoning by heating, at a product temperature of 85°C or above for at least 30 min, an admixture obtained by mixing: a broth obtained by boiling down meats and vegetables miso sugar and water and a step of heating and mixing, with a roux, the miso seasoning thus prepared.