A liquefied seasoning material was manufactured by using the enzymatic hydrolysis for the benefit of highly effective utilization of cockle shell by-product, and their quality was investigated. The weight ratio of by-product to whole cockle shell was 32.7%, and the contents of moisture and crude protein in the raw cockle shell by-product were 83.1% and 10.7%, respectively. The optimal concentrations of protease such as Protease N. P.(Pacific Chemical Co.) and Alcalase(Novo co), used in order to reduced the hydrolysis period, were effective at 4%(w/w), and optimal hydrolyzing time was 8 hours and after 8 hours were little changed. To improve flavor of the liquefied seasoning material, by Maillard reaction used thermal treatment, addition of glucose was very effective. And addition in hydrolysate with 10% glucose, 9% table salt, 2% starch and 0.5% caramel were suitable for promotion of taste. Total nitrogen and amino type nitrogen in the product were 1, 607㎎% and 1, 264㎎%, respectively. And the ratio of amino type nitrogen to the total nitrogen was 78.6%. The major free amino acid were glutamic acid, lysine, leucine, valine and aspartic acid, and content of glutamic acid was 1, 027.5㎎%.