An object of the present invention is to provide a body composition measuring device used in arithmetically deriving an index indicative of body composition in accordance with the bioelectric impedance measuring method, in which a highly accurate calculation result can be obtained with the reduced effect from the fluctuation in a day while using a simple measuring method. Provided is a body composition measuring device in which the bioelectric impedance value is measured at each different frequency by applying the current at a plurality of different frequencies, for example, at a first frequency and a second frequency, to the living body, while concurrently correcting the measured bioelectric impedance value at the first frequency or at the second frequency by using the difference in the bioelectric impedance values between the first and the second frequencies to calculate the index indicative of the body composition based on the corrected bioelectric impedance value, or while concurrently calculating the index indicative of the body composition based on either one of the measured bioelectric impedance values at the first frequency or at the second frequency and then correcting the calculated index indicative of the body composition by using the difference between the bioelectric impedance values at the first and the second frequencies.