Trunk area dimension measurement device and body fat measurement device

A body fat measurement device for measuring a measurement subject who is laying face-up, the body fat measurement device comprising:

• a trunk area dimension measurement device configured to measure a trunk area width and a trunk area depth of the measurement subject, the trunk area dimension measurement device includes:
• a support column to be placed on a side surface of the trunk area of the measurement subject;
• a measurement bar that is supported pivotably about a first support point vertically with respect to the support column and that extends above the trunk area of the measurement subject;
• a distance sensor that is held by the measurement bar positioned above the trunk area of the measurement subject and that is held pivotably about a second support point so as to hang down in a gravity direction, the distance sensor being an optical sensor;
• an angle sensor that is provided at either one of the first support point and the second support point;
• and
• a light reflection portion disposed at a position of a navel of the measurement subject;
• a contact detection unit that is provided on the support column, the contact detection unit being configured to detect contact with the trunk area;
• and
• a control unit configured to process information on an inclination angle of the measurement bar with respect to a vertical direction that is obtained from the angle sensor, information that is obtained from the distance sensor, and information that is obtained from the contact detection unit with respect to the contact with the trunk area,
• the control unit being configured to measure only (i) the distance information, which is a distance between the optical sensor and the light reflection portion, and (ii) the inclination angle information of the measurement bar with respect to the vertical direction obtained from the angle sensor, in order to calculate the trunk area width and trunk area depth of the measurement subject
• the control unit calculating the trunk area depth 2×b based on:
• 2×b=[(h1+h4)−(h2+h3)−2×t]
• wherein h1 is a length from a base position to a first support point, h2 is a length from a second support point to the optical sensor, h3 is a length from the optical sensor to the light reflection portion, h4 is a vertical length from the first support point to the second support point, and t is a thickness of a belt wrapped around the trunk area of the measurement subject.