Abstract: An object of the present invention is to provide a user with a bio-characteristic index in an easily realizable manner by controlling and displaying said index in a long-term viewpoint, and, in particular, to display a transition of user's body fat in an easily sensible manner and to provide a body fat meter employing such display system which allows the user to execute a preferable dieting and to exercise a management of his (her) body weight and body fat. The body fat meter of the present invention graphically displays on a display section simultaneously a daily, a weekly and a monthly variations of past body fat mass stored in a storage section. Further, variation of body weight values is displayed together with that of the body fat mass simultaneously in the same manner thereto. This allows the user to detect an unreasonable dieting where only the fat free tissue decreases but the body fat doesn't decrease, and provides the user with a safe and healthy weight and body fat management system.