Disclosed is an exercise amount measuring device comprising: means for calculating the body fat percentage from the bioelectrical impedance of an individual and the personal data of the individual; means for determining the body shape of the individual and the amount of the basal metabolism of the individual from the personal data and the calculated body fat percentage; means for calculating the "to-be-consumed" body fat amount by subtracting a given body fat percentage set for a goal from the measured body fat percentage; means for calculating the "to-be-consumed" calorie amount required for reducing the "to-be-consumed" body fat amount; means for changing the "to-be-consumed" calorie amount to the corresponding amount of exercise and for setting the so converted amount of exercise as a goal; means for calculating the actual amount of exercise and the consumed calorie amount from the detected motions of the living body and the acceleration of the motion of the living body; and means for calculating the remaining "to-be-consumed" calorie amount, which is given by subtracting the consumed calorie amount from the "to-be-consumed" calorie amount, and the remaining "to-be-attained" exercise amount.