PROBLEM TO BE SOLVED: To obtain a remnant lipoprotein reducing agent and to prepare a funtional food, which can reduce the blood level of remnant lipoprotein that is said to be one of the causes of arteriosclerosis, arterial thrombosis and coronary artery diseases, and can lead to health maintenance and improvement of QOL. SOLUTION: The remnant lipoprotein reducing agent contains, as the active ingredient, water-soluble dietary fibers such as indigestible dextrin. The functional food contains the remnant lipoprotein reducing agent.