Point cloud data that is missed due to an optical reflection object in measuring point cloud data using a laser scanner is used. A reflection object position calculating device includes a point cloud data receiving unit, a three-dimensional point cloud model generating unit, a missing data part searching unit, a missing data part determining unit, and a reflection object position calculator. The point cloud data receiving unit receives point cloud data. The three-dimensional point cloud model generating unit generates a three-dimensional point cloud model from the received point cloud data. The missing data part searching unit searches for a missing data part of the generated three-dimensional point cloud model. The missing data part determining unit determines whether the found missing data part has a predetermined specific shape. The reflection object position calculator calculates three-dimensional coordinates of the missing data part that is determined as having the specific shape.