A body fat measurement device includes a trunk area dimension measurement unit in which is provided a trunk area dimension detection unit for detecting a dimension of a measurement subject's trunk area. The trunk area dimension measurement unit has a frame shape that can be disposed surrounding the measurement subject's trunk area, and includes a base portion whose position relative to the trunk area does not change in a state where the trunk area dimension measurement unit is disposed surrounding the trunk area, and a mobile portion that is attached in a movable state to the base portion and whose position relative to the trunk area can change in a state where the trunk area dimension measurement unit is disposed surrounding the trunk area. The trunk area dimension detection unit includes at least a non-contact range sensor provided in the mobile portion.