A detection portion for detecting a first potential difference between hand and foot by applying a current across the hand and the foot of a subject through both of a hand electrode and a foot electrode and detecting a second potential difference between both hands or between both feet by applying a current across both hands or across both feet of the subject through any one of the hand electrodes and the foot electrodes, a first body composition calculation portion for calculating a first whole-body composition by using whole-body impedance based on a result of detection of the first potential difference, a correction portion for correcting two-limb impedance based on a result of detection of the second potential difference, and a second body composition calculation portion for calculating a second whole-body composition by using the corrected two-limb impedance are included.