Position measuring system

A position measuring system, comprising a rotary laser system having a projection optical system provided at a known point and for projecting a laser beam with a spreading angle in an up-to-bottom direction by rotary irradiation and a photodetection optical system for guiding a reflection light of the laser beam toward an image photodetector, an object having a reflecting body to reflect the laser beam toward the rotary laser system, a GPS position measuring unit for obtaining a position of the object, and a control arithmetic operation unit for calculating an elevation angle with respect to the object from a photodetecting position of the reflection light on the image photodetector and for calculating a position and a height of the object based on position information of the rotary laser system, position information from the GPS position measuring unit and based on the elevation angle.