In a body fat measuring apparatus, a constant electric-current is flowed between hand electric-current electrodes and leg electric-current electrodes. From two detected voltages generated between an annular-shaped voltage electrode placed on an abdominal portion and two voltage electrodes placed at the both sides of a lumbar portion, two abdominal impedances are determined. Two electric-current electrodes and two voltage electrodes are placed such that they are spaced apart by a small interval from one another at an umbilicus portion. A constant electric current is flowed between the two electric-current electrodes and the impedance in the vicinity of the subcutaneous of the abdominal portion is determined from the detected voltage generated between the two voltage electrodes. From the two abdominal impedances, the impedance in the vicinity of the subcutaneous of the abdominal portion, and the input physique information, a viscera impedance is calculated.