A CPU (134) of a body composition measuring apparatus (100) drives a navel position indicator (118) so that it emits light. The height of a frame (114) is adjusted so that a beam of light from navel position indicator (118) irradiates the navel of a human subject. Plural sensors (106) are mounted on the frame (114), and each sensor measures a distance from the sensor to a position to be measured, whereby the abdominal width (X) of the human subject is determined. Subsequently, CPU (134) obtains measured values of weight (W) and bioelectrical impedance (Z). CPU (134) then reads an equation for calculating the visceral fat area and estimates the visceral fat area (Y) based on the measured abdominal width (X), weight (W), bioelectrical impedance (Z), and the equation.