an abdomen width determiner for determining an abdomen width value of a human subject;

a memory for storing a correlation between abdomen width values and waist circumferences of human beings;

a waist circumference calculator for calculating a waist circumference of the human subject on the basis of the abdomen width value determined by the abdomen width determiner and the correlation stored in the memory;

a measuring unit comprising at least one noncontact distance measuring sensor, the sensor emitting light, receiving the light reflected from whatever is in front of the sensor, and generating a signal corresponding to a distance from the sensor to whatever is in front of the sensor,

wherein the abdomen width determiner determines the abdomen width value on the basis of signals generated by the sensor; and

a supporting member that can be disposed in proximity to a human subject,

wherein the measuring unit comprises at least one pair of the noncontact distance measuring sensors supported at the supporting member, the pair of the noncontact distance measuring sensors comprising a first sensor and a second sensor being aligned on opposite sides of the human subject within the supporting member, the first sensor measuring a first gap distance between the first sensor and a first subject position on the human subject in a first measurement line, the second sensor measuring a second gap distance between the second sensor and a second subject position on the human subject in a second measurement line parallel to or identical to the first measurement line, the measuring unit measuring a plurality of first gap distances to a plurality of first subject positions in a plurality of parallel first measurement lines and a plurality of second gap distances to a plurality of second subject positions in a plurality of parallel second measurement lines lying on a plane identical to that in which the first measurement lines lie, and

wherein the abdomen width determiner further comprises:

a distance calculator for calculating a plurality of candidate subject widths on the basis of the plurality of the first gap distances and second gap distances, each candidate subject width being a distance between one of the first subject positions and one of the second subject positions; and

a maximum selector for selecting a maximum subject width as the abdomen width value from among the plurality of candidate subject widths.