Disclosed is an abdominal impedance-based body composition measuring apparatus, which comprises abdominal impedance measurement means for measuring an abdominal impedance, abdominal size estimation means for estimating an abdominal size, and body composition estimation means for estimating an index of body composition, based on the measured abdominal impedance and the estimated abdominal size. The abdominal impedance-based body composition measuring apparatus of the present invention makes it possible to obtain an index of body composition based on an accurate abdominal size.