A surveying system comprises a target and a measuring instrument. The target has retro-reflection characteristics, the measuring instrument comprises a point measuring unit for irradiating a distance measuring light, for receiving a reflected light and for measuring three-dimensional coordinates of the target based on a light receiving result, a scanner unit for rotatably irradiating a laser beam and for acquiring the point cloud data and an arithmetic control module, wherein the point measuring unit measures the target held in the vicinity of an object, the arithmetic control module calculates a region of a three-dimensional space including the object based on a target measurement result of the point measuring unit, the scanner unit scans a predetermined range including the object and acquires the point cloud data, and the arithmetic control module selects the point cloud data only included in the region of the point cloud data.