A visceral fat area of a subject is calculated based on an equation using
as variables a sex of the subject, and an electric impedance ratio
between the longitudinal width of the abdomen and the transversal width
of the abdomen of the subject. As an example of the equation, let the
visceral fat area (cm.sup.2) be VFA and the longitudinal-transversal
impedance ratio of the abdomen be R1, then VFA=a1+b1.times.R1 (where a1
and b1 are constants). A visceral fat area of the subject is also
calculated based on an equation using abdomen circumference as an
additional variable. As an example of the equation, let the abdomen
circumference (cm) be W and the longitudinal-transversal impedance ratio
of the abdomen be R4, then VFA=W.times.(a4+b4.times.R4)+c4 (where a4, b4
and c4 are constants) or VFA=W.sup.2.times.(.alpha.4+.beta.4.times.R4)+.g-
amma.4 (where .alpha.4, .beta.4 and .gamma.4 are constants). The
calculated visceral fat area is compared with the reference value, and
the comparison results are outputted. In the same manner, visceral fat
weight and visceral fat volume can be calculated.
