The circumference of a limb is an important parameter in the follow-up of an edema. Recently, several methods of measuring the circumference on a limb using 3D cameras have been proposed. However, the 3D cameras used are expensive and difficult to implement in general medical facilities. In this study, we propose a circumference-measurement method using a Structure Sensor. First, the leg is photographed and unnecessary background objects are removed from the obtained point cloud. Next, a cross-sectional view is obtained by slicing the point cloud at the specified leg height. Finally, the circumference measurement at a specified leg height is performed by calculating the circumference using the acquired cross-sectional view. Using this method, the leg circumferences of two healthy subjects were measured at two points. For comparison, circumferences were also measured with a measuring tape. The difference between the values estimated using our method and the measured values was generally less than 0.5 cm.