A process is described for continuously drying a paste material for a high-density detergent in a drying apparatus comprising a cylindrical casing and one or more sheet blades radially attached to a rotational shaft positioned at the center of the cylindrical casing such that the tip of each of the one or more sheet blades extends to the inner wall of the cylindrical casing, comprising the steps of feeding a paste material for a high-density detergent having a moisture content of from 20 to 35% by weight into the drying apparatus; forming a film of the paste material on the inner wall of the cylindrical casing by rotating the sheet blades; and scraping the film from the inner wall of the casing while continuously dehydrating and drying the film by heating under vacuum. The process of the invention conserves space and energy in drying the paste material for a high-density detergent. Furthermore, the process of the invention minimizes the deterioration of the paste material for a high-density detergent upon drying.